View source for Biology:Vaccination

{{short description|Administration of a vaccine to protect against disease}}
{{Infobox medical intervention
| Name        = Vaccinations
| Image       = Young girl about to receive a vaccine in her upper arm (48545990252).jpg
| Caption     = Girl about to be vaccinated in her upper arm
| ICD10       =
| ICD9        = {{ICD9proc|99.3}}-{{ICD9proc|99.5}}
| MeshID      =
| OPS301      =
| OtherCodes  =
| HCPCSlevel2 = 
}}

'''Vaccination''' is the administration of a [[Biology:Vaccine|vaccine]] to help the [[Biology:Immune system|immune system]] develop immunity from a disease. Vaccines contain a [[Biology:Microorganism|microorganism]] or [[Biology:Virus|virus]] in a weakened, live or killed state, or [[Biology:Protein|protein]]s or [[Biology:Toxin|toxin]]s from the organism. In stimulating the body's [[Biology:Adaptive immune system|adaptive immunity]], they help prevent sickness from an [[Medicine:Infectious disease|infectious disease]]. When a sufficiently large percentage of a population has been vaccinated, [[Medicine:Herd immunity|herd immunity]] results. Herd immunity protects those who may be immunocompromised and cannot get a vaccine because even a weakened version would harm them.<ref>{{Cite web|title=Herd immunity (Herd protection) {{!}} Vaccine Knowledge|url=https://vk.ovg.ox.ac.uk/vk/herd-immunity|access-date=12 November 2020|website=vk.ovg.ox.ac.uk|archive-date=2 August 2019|archive-url=https://web.archive.org/web/20190802220355/http://vk.ovg.ox.ac.uk/herd-immunity|url-status=live}}</ref> The effectiveness of vaccination has been widely studied and verified.<ref>{{Cite book | vauthors = Fiore AE, Bridges CB, Cox J |chapter=Seasonal Influenza Vaccines |series=Current Topics in Microbiology and Immunology |title=Vaccines for Pandemic Influenza |volume=333 |pages=43–82 |year=2009 |pmid=19768400 |doi=10.1007/978-3-540-92165-3_3 |isbn=978-3-540-92164-6|s2cid=33549265 }}</ref><ref>{{cite journal | vauthors = Chang Y, Brewer NT, Rinas AC, Schmitt K, Smith JS | title = Evaluating the impact of human papillomavirus vaccines | journal = Vaccine | volume = 27 | issue = 32 | pages = 4355–62 | date = July 2009 | pmid = 19515467 | doi = 10.1016/j.vaccine.2009.03.008 }}</ref><ref>{{cite journal | vauthors = Liesegang TJ | title = Varicella zoster virus vaccines: effective, but concerns linger | journal = Canadian Journal of Ophthalmology | volume = 44 | issue = 4 | pages = 379–84 | date = August 2009 | pmid = 19606157 | doi = 10.3129/i09-126 }}</ref> Vaccination is the most effective method of preventing infectious diseases;<ref>{{cite book | title = A CDC framework for preventing infectious diseases | url = https://www.cdc.gov/oid/docs/ID-Framework.pdf | archive-url = https://web.archive.org/web/20120914102409/https://www.cdc.gov/oid/docs/ID-Framework.pdf | archive-date = 14 September 2012 | publisher = United States Centers for Disease Control and Prevention | date = October 2011 | quote = Vaccines are our most effective and cost-saving tools for disease prevention, preventing untold suffering and saving tens of thousands of lives and billions of dollars in healthcare costs each year }}</ref><ref>{{cite web | vauthors = Gellin B | title = Vaccines and Infectious Diseases: Putting Risk into Perspective | url = https://iaomt.org/TestFoundation/lifesaver.htm | archive-url = https://web.archive.org/web/20101124130606/https://iaomt.org/TestFoundation/lifesaver.htm | archive-date = 24 November 2010 | work = American Medical Association Briefing on Microbial Threats | location = National Press Club Washington, DC  | date = 1 June 2000 | quote = Vaccines are the most effective public health tool ever created. }}</ref><ref>{{cite web | title = Vaccine-preventable diseases | date = 7 October 2002 | url = http://www.phac-aspc.gc.ca/im/vpd-mev/index-eng.php | archive-url = https://web.archive.org/web/20120324030536/http://www.phac-aspc.gc.ca/im/vpd-mev/index-eng.php | archive-date = 24 March 2012 | quote = Vaccines still provide the most effective, longest-lasting method of preventing infectious diseases in all age groups | publisher = Public Health Agency of Canada }}</ref><ref>{{cite web | work = United States National Institute of Allergy and Infectious Diseases (NIAID) | url = http://virtualbiosecuritycenter.org/wp-content/uploads/2012/01/Library-NIAID-Biodefense-Research-Agenda-for-Category-B-and-C-Priority-Pathogens.pdf | title = NIAID Biodefense Research Agenda for Category B and C Priority Pathogens | archive-url = https://web.archive.org/web/20160304065419/http://virtualbiosecuritycenter.org/wp-content/uploads/2012/01/Library-NIAID-Biodefense-Research-Agenda-for-Category-B-and-C-Priority-Pathogens.pdf | archive-date = 4 March 2016 | quote = Vaccines are the most effective method of protecting the public against infectious diseases. }}</ref> widespread immunity due to vaccination is largely responsible for the [[Biology:Eradication of infectious diseases|worldwide eradication]] of [[Medicine:Smallpox|smallpox]] and the elimination of diseases such as [[Medicine:Polio|polio]] and [[Medicine:Tetanus|tetanus]] from much of the world. However, some diseases, such as measles outbreaks in America, have seen rising cases due to relatively low vaccination rates in the 2010s – attributed, in part, to [[Unsolved:Vaccine hesitancy|vaccine hesitancy]].<ref>{{cite journal | vauthors = Phadke VK, Bednarczyk RA, Salmon DA, Omer SB | title = Association Between Vaccine Refusal and Vaccine-Preventable Diseases in the United States: A Review of Measles and Pertussis | journal = JAMA | volume = 315 | issue = 11 | pages = 1149–58 | date = March 2016 | pmid = 26978210 | pmc = 5007135 | doi = 10.1001/jama.2016.1353 }}</ref> According to the [[Organization:World Health Organization|World Health Organization]], vaccination prevents 3.5–5&nbsp;million deaths per year.<ref name=":8">{{Cite web |title=Vaccines and immunization |url=https://www.who.int/health-topics/vaccines-and-immunization |access-date=2022-09-18 |website=[[Organization:World Health Organization|World Health Organization]] |language=en |archive-date=1 January 2022 |archive-url=https://web.archive.org/web/20220101135141/https://www.who.int/health-topics/vaccines-and-immunization |url-status=live }}</ref>

The first disease people tried to prevent by [[Biology:Inoculation|inoculation]] was most likely smallpox, with the first recorded use of [[Biology:Variolation|variolation]] occurring in the 16th century in China.{{sfn|Williams|2010|p=60}} It was also the first disease for which a vaccine was produced.<ref name="pmid17633292">{{cite journal | vauthors = Lombard M, Pastoret PP, Moulin AM | s2cid = 6688481 | title = A brief history of vaccines and vaccination | journal = Revue Scientifique et Technique | volume = 26 | issue = 1 | pages = 29–48 | date = April 2007 | pmid = 17633292 | doi = 10.20506/rst.26.1.1724 | doi-access = free }}</ref><ref name="pmid6319980">{{cite journal | vauthors = Behbehani AM | title = The smallpox story: life and death of an old disease | journal = Microbiological Reviews | volume = 47 | issue = 4 | pages = 455–509 | date = December 1983 | pmid = 6319980 | pmc = 281588 | doi =  10.1128/MMBR.47.4.455-509.1983}}</ref> Although at least six people had used the same principles years earlier, the [[Medicine:Smallpox vaccine|smallpox vaccine]] was invented in 1796 by English physician Edward Jenner. He was the first to publish evidence that it was effective and to provide advice on its production.<ref name="Sudhoffs">{{cite journal | vauthors = Plett PC | title = [Peter Plett and other discoverers of cowpox vaccination before Edward Jenner] | language = de | journal = Sudhoffs Archiv | volume = 90 | issue = 2 | pages = 219–32 | year = 2006 | pmid = 17338405 | url = http://lib.bioinfo.pl/meid:4459 | access-date = 12 March 2008 | archive-url = https://web.archive.org/web/20080215171503/http://lib.bioinfo.pl/meid:4459 | archive-date = 15 February 2008 | url-status = dead }}</ref> Louis Pasteur furthered the concept through his work in microbiology. The [[Biology:Immunization|immunization]] was called ''vaccination'' because it was derived from a virus affecting cows ({{lang-la|vacca}} 'cow').<ref name="pmid17633292" /><ref name="Sudhoffs" /> Smallpox was a contagious and deadly disease, causing the deaths of 20–60% of infected adults and over 80% of infected children.<ref>{{cite journal | vauthors = Riedel S | title = Edward Jenner and the history of smallpox and vaccination | journal = Proceedings | volume = 18 | issue = 1 | pages = 21–5 | date = January 2005 | pmid = 16200144 | pmc = 1200696 | doi = 10.1080/08998280.2005.11928028 }}</ref> When smallpox was finally eradicated in 1979, it had already killed an estimated 300–500&nbsp;million people in the 20th century.<ref>{{cite book|url=https://archive.org/details/smallpoxfighttoe00kopl|url-access=registration|title=Smallpox: the fight to eradicate a global scourge| vauthors = Koplow DA |publisher=University of California Press|year=2003|isbn=978-0-520-24220-3|location=Berkeley}}</ref><ref>{{cite web|url=http://ucdavismagazine.ucdavis.edu/issues/su06/feature_1b.html|title=UC Davis Magazine, Summer 2006: Epidemics on the Horizon|archive-url=https://web.archive.org/web/20081211181455/http://ucdavismagazine.ucdavis.edu/issues/su06/feature_1b.html|archive-date=11 December 2008|url-status=dead|access-date=3 January 2008}}</ref><ref>{{Cite web |title=How Poxviruses Such As Smallpox Evade The Immune System |url=https://www.sciencedaily.com/releases/2008/01/080131122956.htm |access-date=2023-10-17 |website=ScienceDaily |language=en |archive-date=28 February 2020 |archive-url=https://web.archive.org/web/20200228180621/https://www.sciencedaily.com/releases/2008/01/080131122956.htm |url-status=live }}</ref>

''Vaccination'' and ''[[Biology:Immunization|immunization]]'' have a similar meaning in everyday language. This is distinct from inoculation, which uses unweakened live pathogens. Vaccination efforts have been met with some reluctance on scientific, ethical, political, medical safety, and religious grounds, although no major religions oppose vaccination, and some consider it an obligation due to the potential to save lives.<ref name="nyt19">{{cite web |vauthors=McNeil DG |title=Religious Objections to the Measles Vaccine? Get the Shots, Faith Leaders Say |url=https://www.nytimes.com/2019/04/26/health/measles-vaccination-jews-muslims-catholics.html |website=The New York Times |access-date=29 April 2019 |date=26 April 2019 |archive-date=28 April 2019 |archive-url=https://web.archive.org/web/20190428222245/https://www.nytimes.com/2019/04/26/health/measles-vaccination-jews-muslims-catholics.html |url-status=live }}</ref> In the United States, people may receive compensation for alleged injuries under the [[Medicine:National Vaccine Injury Compensation Program|National Vaccine Injury Compensation Program]]. Early success brought widespread acceptance, and mass vaccination campaigns have greatly reduced the incidence of many diseases in numerous geographic regions. The Centers for Disease Control and Prevention lists vaccination as one of the ten great public health achievements of the 20th century in the U.S.<ref name="Ten-great">{{cite journal |vauthors=CDC |date=April 1999 |title=Ten great public health achievements--United States, 1900-1999 |url=http://cdc.gov/mmwr/preview/mmwrhtml/00056796.htm |journal=MMWR. Morbidity and Mortality Weekly Report |volume=48 |issue=12 |pages=241–3 |pmid=10220250 |access-date=16 April 2022 |archive-date=11 July 2011 |archive-url=https://web.archive.org/web/20110711150635/http://www.cdc.gov/mmwr/preview/mmwrhtml/00056796.htm |url-status=live }}</ref>

==Mechanism of function==
[[File:Polio vaccination in Sweden 1957.jpg|thumb|upright=0.8|In Sweden, polio vaccination started in 1957.]]
[[File:Punkkibussi.jpg|thumb|A mobile medicine laboratory providing vaccinations against diseases spread by [[Biology:Tick|tick]]s]]
[[File:Anti-COVID-19 Vaccination Center GUMed Gdansk Poland.jpg|thumb|COVID-19 Vaccination Center of the Medical University of Gdańsk, {{wipe|Poland}}]]
Vaccines are a way of artificially activating the immune system to protect against [[Medicine:Infectious disease|infectious disease]]. The activation occurs through priming the [[Biology:Immune system|immune system]] with an [[Biology:Immunogen|immunogen]].  Stimulating immune responses with an infectious agent is known as ''[[Biology:Immunization|immunization]]''. Vaccination includes various ways of administering immunogens.<ref>{{cite journal | vauthors = Kwong PD | title = What Are the Most Powerful Immunogen Design Vaccine Strategies? A Structural Biologist's Perspective | journal = Cold Spring Harbor Perspectives in Biology | volume = 9 | issue = 11 | pages = a029470 | date = November 2017 | pmid = 28159876 | pmc = 5666634 | doi = 10.1101/cshperspect.a029470 }}</ref>

Most vaccines are administered before a patient has contracted a disease to help increase future protection. However, some vaccines are administered after the patient already has contracted a disease. Vaccines given after exposure to smallpox are reported to offer some protection from disease or may reduce the severity of disease.<ref name="CDCvac">{{cite web |url=http://www.bt.cdc.gov/agent/smallpox/vaccination/pdf/vaccine-overview.pdf |title=Vaccine Overview |access-date=2 January 2008 |website=Smallpox Fact Sheet |archive-url=https://web.archive.org/web/20080102234114/http://www.bt.cdc.gov/agent/smallpox/vaccination/pdf/vaccine-overview.pdf |archive-date=2 January 2008 |url-status=dead}}</ref> The first [[Medicine:Rabies|rabies]] immunization was given by Louis Pasteur to a child after he was bitten by a [[Medicine:Rabies|rabid]] dog. Since its discovery, the rabies vaccine has been proven effective in preventing rabies in humans when administered several times over 14 days along with rabies immune globulin and wound care.<ref>{{cite journal | vauthors = Rupprecht CE, Briggs D, Brown CM, Franka R, Katz SL, Kerr HD, Lett SM, Levis R, Meltzer MI, Schaffner W, Cieslak PR | display-authors = 6 | title = Use of a reduced (4-dose) vaccine schedule for postexposure prophylaxis to prevent human rabies: recommendations of the advisory committee on immunization practices | journal = MMWR. Recommendations and Reports | volume = 59 | issue = RR-2 | pages = 1–9 | date = March 2010 | pmid = 20300058 }}</ref> Other examples include experimental AIDS, cancer<ref>{{cite journal | vauthors = Oppenheimer SB, Alvarez M, Nnoli J | title = Carbohydrate-based experimental therapeutics for cancer, HIV/AIDS and other diseases | journal = Acta Histochemica | volume = 110 | issue = 1 | pages = 6–13 | date = 2008 | pmid = 17963823 | pmc = 2278011 | doi = 10.1016/j.acthis.2007.08.003 }}</ref> and [[Medicine:Alzheimer's disease|Alzheimer's disease]] vaccines.<ref>{{cite journal | vauthors = Goñi F, Sigurdsson EM | title = New directions towards safer and effective vaccines for Alzheimer's disease | journal = Current Opinion in Molecular Therapeutics | volume = 7 | issue = 1 | pages = 17–23 | date = February 2005 | pmid = 15732525 }}</ref> Such immunizations aim to trigger an immune response more rapidly and with less harm than natural infection.<ref>{{cite journal | vauthors = Irvine DJ, Swartz MA, Szeto GL | title = Engineering synthetic vaccines using cues from natural immunity | journal = Nature Materials | volume = 12 | issue = 11 | pages = 978–90 | date = November 2013 | pmid = 24150416 | pmc = 3928825 | doi = 10.1038/nmat3775 | bibcode = 2013NatMa..12..978I }}</ref>

Most vaccines are given by injection as they are not absorbed reliably through the intestines. Live attenuated polio, rotavirus, some typhoid, and some cholera vaccines are given orally to produce immunity in the bowel. While vaccination provides a lasting effect, it usually takes several weeks to develop. This differs from [[Biology:Passive immunity|passive immunity]] (the transfer of [[Biology:Antibodies|antibodies]], such as in breastfeeding), which has immediate effect.<ref>{{cite web|url=https://www.cdc.gov/vaccines/vac-gen/immunity-types.htm|title=Immunity Types|publisher=Centers for Disease Control and Prevention|access-date=20 October 2015|archive-date=22 December 2011|archive-url=https://web.archive.org/web/20111222052748/http://cdc.gov/vaccines/vac-gen/immunity-types.htm|url-status=live}}</ref>

A vaccine failure is when an organism contracts a disease in spite of being vaccinated against it. Primary [[Biology:Vaccine|vaccine]] failure occurs when an organism's immune system does not produce [[Biology:Antibody|antibodies]] when first vaccinated. Vaccines can fail when several series are given and fail to produce an immune response. The term "vaccine failure" does not necessarily imply that the vaccine is defective. Most vaccine failures are simply due to individual variations in immune response.<ref>{{cite journal | vauthors = Wiedermann U, Garner-Spitzer E, Wagner A | title = Primary vaccine failure to routine vaccines: Why and what to do? | journal = Human Vaccines & Immunotherapeutics | volume = 12 | issue = 1 | pages = 239–43 | date = 2016 | pmid = 26836329 | pmc = 4962729 | doi = 10.1080/21645515.2015.1093263 }}</ref>
[[File:Measles-vaccine-coverage-worldwide-vs-measles-cases-worldwide.png|alt=|thumb|Measles infection rate vs. vaccination rate, 1980–2011. Source: WHO]]

===Vaccination versus inoculation===
The term "[[Biology:Inoculation|inoculation]]" is often used interchangeably with "vaccination." However, while related, the terms are not synonymous. Vaccination is treatment of an individual with an attenuated (i.e. less virulent) [[Biology:Pathogen|pathogen]] or other [[Biology:Immunogen|immunogen]], whereas inoculation, also called [[Biology:Variolation|variolation]] in the context of [[Medicine:Smallpox|smallpox]] prophylaxis, is treatment with unattenuated variola virus taken from a pustule or scab of a smallpox patient into the superficial layers of the skin, commonly the upper arm. Variolation was often done 'arm-to-arm' or, less effectively, 'scab-to-arm', and often caused the patient to become infected with smallpox, which in some cases resulted in severe disease.<ref>{{Cite web|url=http://web.uvic.ca/vv/student/smallpox/doctors/diff.html|title=The Smallpox Epidemic of 1862 (Victoria BC)--Doctors and Diagnosis|website=web.uvic.ca|access-date=29 September 2016|archive-date=2 February 2018|archive-url=https://web.archive.org/web/20180202203718/http://web.uvic.ca/vv/student/smallpox/doctors/diff.html|url-status=live}}</ref><ref>{{cite web |url=http://web.uvic.ca/vv/student/smallpox/doctors/diff.html |title=Doctors and diagnosis ''The difference between Vaccination and Inoculation'' |publisher=Web.uvic.ca |access-date=8 January 2014 |archive-date=2 February 2018 |archive-url=https://web.archive.org/web/20180202203718/http://web.uvic.ca/vv/student/smallpox/doctors/diff.html |url-status=live }}</ref>

Vaccinations began in the late 18th century with the work of Edward Jenner and the smallpox vaccine.<ref>{{cite news |title=Edward Jenner – (1749–1823) |publisher=Sundaytimes.lk. |date=1 June 2008 |url=http://sundaytimes.lk/080601/FunDay/famous.html |access-date=28 July 2009 |archive-url=https://web.archive.org/web/20110926095825/http://sundaytimes.lk/080601/FunDay/famous.html |archive-date=26 September 2011 |url-status=dead }}</ref><ref>{{cite web |url=https://www.bbc.co.uk/history/historic_figures/jenner_edward.shtml |title=History – Edward Jenner (1749–1823) |publisher=BBC |access-date=1 March 2014 |archive-date=8 March 2021 |archive-url=https://web.archive.org/web/20210308032314/https://www.bbc.co.uk/history/historic_figures/jenner_edward.shtml |url-status=live }}</ref><ref>{{cite web|url=http://www.dinweb.org/dinweb/DINMuseum/Edward%20Jenner.asp|title=Edward Jenner – Smallpox and the Discovery of Vaccination|website=dinweb.org|access-date=22 April 2010|archive-url=https://web.archive.org/web/20100827080455/http://www.dinweb.org/dinweb/DINMuseum/Edward%20Jenner.asp|archive-date=27 August 2010|url-status=dead}}</ref>

===Preventing disease versus preventing infection===

Some vaccines, like the smallpox vaccine, prevent infection. Their use results in sterilizing immunity and can help eradicate a disease if there is no animal reserve. Other vaccines, including those for {{Nowrap|[[Medicine:COVID-19|COVID-19]]}}, help to (temporarily) lower the chance of severe disease for individuals, without necessarily reducing the probability of becoming infected.<ref>{{Cite web |url=https://theconversation.com/coronavirus-few-vaccines-prevent-infection-heres-why-thats-not-a-problem-152204 |title=Coronavirus: few vaccines prevent infection – here's why that's not a problem |date=5 January 2021 |last=Caddy |first=Sarah L. |website=The Conversation |access-date=18 December 2022 |archive-date=18 December 2022 |archive-url=https://web.archive.org/web/20221218103955/https://theconversation.com/coronavirus-few-vaccines-prevent-infection-heres-why-thats-not-a-problem-152204 |url-status=live }}</ref>

== Safety ==
{{Further|Unsolved:Vaccine hesitancy|Medicine:Vaccine adverse event}}
[[File:Global-smallpox-cases.png|thumb|Global smallpox cases from 1920 to 2010. Source: WHO]]

=== Vaccine development and approval ===
Just like any medication or procedure, no vaccine can be 100% safe or effective for everyone because each person's body can react differently.<ref>{{Cite web|url=https://www.cdc.gov/vaccinesafety/ensuringsafety/history/index.html|title=History of Vaccine Safety History Ensuring Safety Vaccine Safety CDC|date=10 January 2019|website=www.cdc.gov|access-date=12 March 2019|archive-date=28 March 2019|archive-url=https://web.archive.org/web/20190328070048/https://www.cdc.gov/vaccinesafety/ensuringsafety/history/index.html|url-status=live}}</ref><ref name=":6">{{cite journal | vauthors = Chen RT, Hibbs B | s2cid = 13364842 | title = Vaccine safety: current and future challenges | journal = Pediatric Annals | volume = 27 | issue = 7 | pages = 445–55 | date = July 1998 | pmid = 9677616 | doi = 10.3928/0090-4481-19980701-11 }}</ref> While minor [[Medicine:Side effect|side effect]]s, such as soreness or low grade fever, are relatively common, serious side effects are very rare and occur in about 1 out of every 100,000 vaccinations and typically involve [[Medicine:Allergy|allergic reactions]] that can cause hives or difficulty breathing.<ref name=":2">{{Cite web|url=https://www.niaid.nih.gov/research/making-safe-vaccines|title=Making Safe Vaccines NIH: National Institute of Allergy and Infectious Diseases|website=www.niaid.nih.gov|access-date=12 March 2019|archive-date=28 March 2019|archive-url=https://web.archive.org/web/20190328065701/https://www.niaid.nih.gov/research/making-safe-vaccines|url-status=live}}</ref><ref name=":1">{{Cite web|url=https://www.cdc.gov/vaccines/vac-gen/side-effects.htm|title=Vaccines: Vac-Gen/Side Effects|date=12 July 2018|website=www.cdc.gov|access-date=12 March 2019|archive-date=17 March 2017|archive-url=https://web.archive.org/web/20170317050028/https://www.cdc.gov/vaccines/vac-gen/side-effects.htm|url-status=live}}</ref>

However, vaccines are the safest they ever have been in history and each vaccine undergoes rigorous clinical trials to ensure their safety and efficacy before approval by authorities such as the US [[Organization:Food and Drug Administration|Food and Drug Administration]] (FDA).<ref name=":3">{{Cite web|url=https://www.cdc.gov/vaccinesafety/ensuringsafety/index.html|title=Ensuring Vaccine Safety Ensuring Safety Vaccine Safety CDC|date=12 December 2018|website=www.cdc.gov|access-date=12 March 2019|archive-date=12 March 2019|archive-url=https://web.archive.org/web/20190312165811/https://www.cdc.gov/vaccinesafety/ensuringsafety/index.html|url-status=live}}</ref>

Prior to human testing, vaccines are tested on [[Biology:Cell culture|cell culture]]s and the results modelled to assess how they will interact with the immune system.<ref name=":2" /><ref name=":3" /> During the next round of testing, researchers study vaccines in animals, including [[Biology:Mouse|mice]], [[Biology:Rabbit|rabbit]]s, [[Biology:Guinea pig|guinea pig]]s, and [[Biology:Monkey|monkey]]s.<ref name=":2" /> Vaccines that pass each of these stages of testing are then approved by the public health safety authority (FDA in the United States) to start a three-phase series of human testing, advancing to higher phases only if they are deemed safe and effective at the previous phase. The people in these trials participate voluntarily and are required to prove they understand the purpose of the study and the potential risks.<ref name=":3" />

During phase I trials, a vaccine is tested in a group of about 20 people with the primary goal of assessing the vaccine's safety.<ref name=":2" /> Phase II trials expand the testing to include 50 to several hundred people. During this stage, the vaccine's safety continues to be evaluated and researchers also gather data on the effectiveness and the ideal dose of the vaccine.<ref name=":2" /> Vaccines determined to be safe and efficacious then advance to phase III trials, which focuses on the efficacy of the vaccine in hundreds to thousands of volunteers. This phase can take several years to complete and researchers use this opportunity to compare the vaccinated volunteers to those who have not been vaccinated to highlight any true reactions to the vaccine that occur.<ref name=":3" />

If a vaccine passes all of the phases of testing, the manufacturer can then apply for license of the vaccine through the relevant regulatory authorities such as the FDA in US. Before regulatory authorities approve use in the general public, they extensively review the results of the clinical trials, safety tests, purity tests, and manufacturing methods and establish that the manufacturer itself is up to government standards in many other areas.<ref name=":2" /><ref name=":who_vac_dev">{{Cite web|url=https://www.who.int/news-room/feature-stories/detail/how-are-vaccines-developed|title=How are vaccines developed? WHO|date=8 December 2020|website=www.who.int|access-date=26 October 2023|archive-date=26 October 2023|archive-url=https://web.archive.org/web/20231026062500/https://www.who.int/news-room/feature-stories/detail/how-are-vaccines-developed|url-status=live}}</ref>

After regulatory approval, the regulators continue to monitor the manufacturing protocols, batch purity, and the manufacturing facility itself. Additionally, vaccines also undergo phase IV trials, which monitor the safety and efficacy of vaccines in tens of thousands of people, or more, across many years.<ref name=":2" /><ref name=":who_vac_dev" />

=== Side effects ===
The Centers for Disease Control and Prevention (CDC) has compiled a list of vaccines and their possible side effects.<ref name=":1" /> The risk of side effects varies between vaccines.

=== Notable vaccine investigations ===
In 1976 in the United States, a mass [[Biology:1976 swine flu outbreak|a swine flu vaccination programme]] was discontinued after 362 cases of [[Medicine:Guillain–Barré syndrome|Guillain–Barré syndrome]] among 45 million vaccinated people. William Foege of the CDC estimated that the incidence of Guillain-Barré was four times higher in vaccinated people than in those not receiving the swine flu vaccine.

Dengvaxia, the only approved vaccine for [[Medicine:Dengue fever|Dengue fever]], was found to increase the risk of hospitalization for Dengue fever by 1.58 times in children of 9 years or younger, resulting in the suspension of a mass vaccination program in the Philippines in 2017.<ref>{{cite journal | vauthors = Redoni M, Yacoub S, Rivino L, Giacobbe DR, Luzzati R, Di Bella S | title = Dengue: Status of current and under-development vaccines | journal = Reviews in Medical Virology | volume = 30 | issue = 4 | pages = e2101 | date = July 2020 | pmid = 32101634 | doi = 10.1002/rmv.2101 | hdl-access = free | s2cid = 211536962 | hdl = 1983/6d38d9b6-8e1b-4a84-85e3-edab4fc41957 | url = https://research-information.bris.ac.uk/en/publications/6d38d9b6-8e1b-4a84-85e3-edab4fc41957 | access-date = 23 September 2021 | archive-date = 20 March 2022 | archive-url = https://web.archive.org/web/20220320141819/https://research-information.bris.ac.uk/en/publications/dengue-status-of-current-and-under-development-vaccines | url-status = live }}</ref>

[[Chemistry:Pandemrix|Pandemrix]] {{ndash}} a vaccine for the [[Medicine:2009 swine flu pandemic vaccine|H1N1]] pandemic of 2009 given to around 31 million people<ref name=":6" /> {{ndash}} was found to have a higher level of adverse events than alternative vaccines resulting in legal action.<ref>{{cite journal | title = Pandemrix vaccine: why was the public not told of early warning signs? | journal = BMJ | volume = 362 | pages = k3948 | date = 20 September 2018 | pmid = 30237282 | doi = 10.1136/bmj.k3948 | s2cid = 52308748 | last1 = Doshi | first1 = Peter }}</ref> In a response to the [[Medicine:Narcolepsy|narcolepsy]] reports following immunization with Pandemrix, the CDC carried out a population-based study and found the FDA-approved 2009 H1N1 flu shots were not associated with an increased risk for the neurological disorder.<ref>{{Cite web|url=https://www.cdc.gov/vaccinesafety/concerns/history/narcolepsy-flu.html|title=Narcolepsy Following Pandemrix in Europe|date=20 August 2020|website=www.cdc.gov|access-date=3 January 2021|archive-date=27 June 2016|archive-url=https://web.archive.org/web/20160627180432/http://www.cdc.gov/vaccinesafety/concerns/history/narcolepsy-flu.html|url-status=live}}</ref>

=== Ingredients ===
The ingredients of vaccines can vary greatly from one to the next and no two vaccines are the same. The CDC has compiled a list of vaccines and their ingredients that is readily accessible on their website.<ref>{{Cite web|url=https://www.cdc.gov/vaccines/vac-gen/additives.htm|title=Vaccines: Vac-Gen/Additives in Vaccines Fact Sheet|date=12 July 2018|website=www.cdc.gov|access-date=15 March 2019|archive-date=30 May 2019|archive-url=https://web.archive.org/web/20190530215608/https://www.cdc.gov/vaccines/vac-gen/additives.htm|url-status=live}}</ref>

==== Aluminium ====
[[Chemistry:Aluminium|Aluminium]] is an adjuvant ingredient in some vaccines. An adjuvant is a type of ingredient that is used to help the body's immune system create a stronger immune response after receiving the vaccination.<ref name=":4">{{Cite web|url=https://www.cdc.gov/vaccinesafety/concerns/adjuvants.html|title=Adjuvants help vaccines work better. Vaccine Safety CDC|date=23 January 2019|website=www.cdc.gov|access-date=15 March 2019|archive-date=15 March 2019|archive-url=https://web.archive.org/web/20190315224921/https://www.cdc.gov/vaccinesafety/concerns/adjuvants.html|url-status=live}}</ref> Aluminium is in a [[Chemistry:Salt|salt]] form (the ionic version of an element) and is used in the following compounds: [[Chemistry:Aluminium hydroxide|aluminium hydroxide]], [[Chemistry:Aluminium phosphate|aluminium phosphate]], and aluminium potassium sulfate. For a given element, the [[Physics:Ion|ion]] form has different properties from the elemental form. Although it is possible to have [[Medicine:Aluminium toxicity in people on dialysis|aluminium toxicity]], aluminium salts have been used effectively and safely since the 1930s when they were first used with the [[Medicine:Diphtheria|diphtheria]] and [[Medicine:Tetanus|tetanus]] vaccines.<ref name=":4" /> Although there is a small increase in the chance of having a local reaction to a vaccine with an aluminium salt (redness, soreness, and swelling), there is no increased risk of any serious reactions.<ref>{{cite journal | vauthors = Jefferson T, Rudin M, Di Pietrantonj C | title = Adverse events after immunisation with aluminium-containing DTP vaccines: systematic review of the evidence | journal = The Lancet. Infectious Diseases | volume = 4 | issue = 2 | pages = 84–90 | date = February 2004 | pmid = 14871632 | doi = 10.1016/S1473-3099(04)00927-2 }}</ref><ref>{{cite journal | vauthors = Mitkus RJ, King DB, Hess MA, Forshee RA, Walderhaug MO | title = Updated aluminum pharmacokinetics following infant exposures through diet and vaccination | journal = Vaccine | volume = 29 | issue = 51 | pages = 9538–43 | date = November 2011 | pmid = 22001122 | doi = 10.1016/j.vaccine.2011.09.124 | doi-access = free }}</ref>

==== Mercury ====
Certain vaccines once contained a compound called [[Chemistry:Thiomersal|thiomersal]] or thimerosal, which is an [[Chemistry:Organic compound|organic compound]] containing [[Chemistry:Mercury (element)|mercury]]. [[Chemistry:Organomercury|Organomercury]] is commonly found in two forms. The [[Chemistry:Methylmercury|methylmercury]] cation (with one carbon atom) is found in mercury-contaminated fish and is the form that people might ingest in mercury-polluted areas (Minamata disease), whereas the [[Chemistry:Ethylmercury|ethylmercury]] cation (with two carbon atoms) is present in thimerosal, linked to [[Chemistry:Thiosalicylic acid|thiosalicylate]].<ref name=":5">{{Cite web|url=https://www.cdc.gov/vaccinesafety/concerns/thimerosal/index.html|title=Thimerosal in Vaccines Thimerosal Concerns Vaccine Safety CDC|date=24 January 2019|website=www.cdc.gov|access-date=22 March 2019|archive-date=17 August 2011|archive-url=https://web.archive.org/web/20110817063316/http://www.cdc.gov/vaccinesafety/concerns/thimerosal/index.html|url-status=live}}</ref> Although both are organomercury compounds, they do not have the same chemical properties and interact with the human body differently.  Ethylmercury is cleared from the body faster than methylmercury and is less likely to cause toxic effects.<ref name=":5" />

Thimerosal was used as a [[Chemistry:Preservative|preservative]] to prevent the growth of [[Biology:Bacteria|bacteria]] and [[Biology:Fungus|fungi]] in vials that contain more than one dose of a vaccine.<ref name=":5" /> This helps reduce the risk of potential [[Medicine:Infection|infection]]s or serious illness that could occur from [[Chemistry:Contamination|contamination]] of a vaccine vial.  Although there was a small increase in risk of injection site redness and swelling with vaccines containing thimerosal, there was no increased risk of serious harm or [[Medicine:Autism|autism]].<ref>{{cite journal | vauthors = Ball LK, Ball R, Pratt RD | title = An assessment of thimerosal use in childhood vaccines | journal = Pediatrics | volume = 107 | issue = 5 | pages = 1147–54 | date = May 2001 | pmid = 11331700 | doi = 10.1542/peds.107.5.1147 }}</ref><ref>{{Cite web|url=https://www.fda.gov/BiologicsBloodVaccines/SafetyAvailability/VaccineSafety/UCM096228#bib|title=Vaccine Safety & Availability - Thimerosal and Vaccines|website=www.fda.gov|access-date=22 March 2019|archive-date=6 January 2013|archive-url=https://web.archive.org/web/20130106215029/https://www.fda.gov/BiologicsBloodVaccines/SafetyAvailability/VaccineSafety/UCM096228#bib|url-status=live}}</ref> Even though evidence supports the safety and efficacy of thimerosal in vaccines, thimerosal was removed from childhood vaccines in the United States in 2001 as a precaution.<ref name=":5" />

=== Monitoring ===

CDC Immunization Safety Office initiatives<ref name="cdc">{{Cite web|url=https://www.cdc.gov/vaccinesafety/ensuringsafety/monitoring/index.html|title=Vaccine Safety Monitoring Monitoring Ensuring Safety Vaccine Safety CDC|date=12 December 2018|website=www.cdc.gov|access-date=24 March 2019|archive-date=30 March 2019|archive-url=https://web.archive.org/web/20190330112053/https://www.cdc.gov/vaccinesafety/ensuringsafety/monitoring/index.html|url-status=live}}</ref>

Vaccine Adverse Event Reporting System ([[Medicine:Vaccine Adverse Event Reporting System|VAERS]])<ref>{{Cite web|url=https://vaers.hhs.gov/|title=Vaccine Adverse Event Reporting System (VAERS)|website=vaers.hhs.gov|access-date=24 March 2019|archive-date=17 March 2019|archive-url=https://web.archive.org/web/20190317025059/https://vaers.hhs.gov/|url-status=live}}</ref>
|Food and Drug Administration ([[Organization:Food and Drug Administration|FDA]]) Center for Biologics Evaluation and Research ([[Organization:Center for Biologics Evaluation and Research|CBER]])<ref>{{Cite web|url=https://www.fda.gov/aboutfda/centersoffices/officeofmedicalproductsandtobacco/cber/|title=About the Center for Biologics Evaluation and Research (CBER)|website=www.fda.gov|access-date=24 March 2019|date=7 February 2019|archive-date=9 May 2017|archive-url=https://web.archive.org/web/20170509063921/https://www.fda.gov/AboutFDA/CentersOffices/OfficeofMedicalProductsandTobacco/CBER/|url-status=live}}</ref>
|Immunization Action Coalition (IAC)<ref>{{Cite web|url=http://www.immunize.org/|title=Immunization Action Coalition (IAC): Vaccine Information for Health Care Professionals|website=www.immunize.org|access-date=24 March 2019|archive-date=14 December 2017|archive-url=https://web.archive.org/web/20171214105220/http://www.immunize.org/catg.d/p4209.pdf|url-status=live}}</ref>

Vaccine Safety Datalink ([[Medicine:Vaccine Safety Datalink|VSD]])<ref>{{Cite web|url=https://www.cdc.gov/vaccinesafety/ensuringsafety/monitoring/vsd/index.html|title=Vaccine Safety Datalink (VSD) VSD Monitoring Ensuring Safety Vaccine Safety CDC|date=10 January 2019|website=www.cdc.gov|access-date=24 March 2019|archive-date=30 March 2019|archive-url=https://web.archive.org/web/20190330105907/https://www.cdc.gov/vaccinesafety/ensuringsafety/monitoring/vsd/index.html|url-status=live}}</ref>
|Health Resources and Service Administration (HRSA)<ref>{{Cite web|url=https://www.hrsa.gov/|title=Official web site of the U.S. Health Resources & Services Administration|website=www.hrsa.gov|access-date=24 March 2019|archive-date=23 March 2019|archive-url=https://web.archive.org/web/20190323220751/https://www.hrsa.gov/|url-status=live}}</ref>
|Institute for Safe Medication Practices (ISMP)<ref>{{Cite web|url=https://www.ismp.org/home|title=Home|website=Institute For Safe Medication Practices|access-date=24 March 2019|archive-date=20 March 2022|archive-url=https://web.archive.org/web/20220320141815/https://www.ismp.org/|url-status=live}}</ref>

Clinical Immunization Safety Assessment (CISA) Project
National Institutes of Health ([[Organization:National Institutes of Health|NIH]])<ref>{{Cite web|url=https://www.nih.gov/|title=National Institutes of Health (NIH)|website=National Institutes of Health (NIH)|access-date=24 March 2019|archive-date=2 October 2019|archive-url=https://web.archive.org/web/20191002092840/https://www.nih.gov/|url-status=live}}</ref>

National Vaccine Program Office (NVPO)<ref>{{Cite web|url=https://www.hhs.gov/nvpo/index.html|title=National Vaccine Program Office (NVPO)|date=30 March 2016|website=HHS.gov|access-date=24 March 2019|archive-date=24 March 2019|archive-url=https://web.archive.org/web/20190324210714/https://www.hhs.gov/nvpo/index.html|url-status=live}}</ref>

The administration protocols, efficacy, and adverse events of vaccines are monitored by organizations of the US federal government, including the CDC and FDA, and independent agencies are constantly re-evaluating vaccine practices.<ref name=cdc/><ref name="canada">{{Cite web|url=https://www.canada.ca/en/public-health/services/immunization/vaccine-safety.html|title=Vaccine safety, surveillance and reporting|publisher=Government of Canada|date=22 April 2014|access-date=14 April 2020|archive-date=13 April 2020|archive-url=https://web.archive.org/web/20200413031419/https://www.canada.ca/en/public-health/services/immunization/vaccine-safety.html|url-status=live}}</ref> As with all medications, vaccine use is determined by public health research, surveillance, and reporting to governments and the public.<ref name=cdc/><ref name=canada/>

==Usage==
[[File:Share of children who receive key vaccines in target populations, OWID.svg|thumb|upright=1.6|Share of children who received key vaccines in 2016<ref>{{cite web |title=Share of children who receive key vaccines in target populations |url=https://ourworldindata.org/grapher/coverage-of-key-vaccines-sdgs |website=Our World in Data |access-date=5 March 2020 |archive-date=5 May 2020 |archive-url=https://web.archive.org/web/20200505130309/https://ourworldindata.org/grapher/coverage-of-key-vaccines-sdgs |url-status=dead }}</ref>]]
[[File:Global-vaccination-coverage.png|thumb|upright=1.6|Global vaccination coverage among one year olds (1980–2019)<ref>{{cite web |title=Global vaccination coverage |url=https://ourworldindata.org/grapher/global-vaccination-coverage?time=1980..2018 |website=Our World in Data |access-date=5 March 2020 |archive-date=3 July 2020 |archive-url=https://web.archive.org/web/20200703105611/https://ourworldindata.org/grapher/global-vaccination-coverage?time=1980..2018 |url-status=live }}</ref>]]

The [[Organization:World Health Organization|World Health Organization]] (WHO) has estimated that vaccination prevents 3.5–5&nbsp;million deaths per year,<ref name=":8" /> and up to 1.5&nbsp;million children die each year due to [[Medicine:Vaccine-preventable disease|diseases that could have been prevented by vaccination]].<ref name="WHO_vaccination_report">{{cite web | title= Global Immunization Data | url= https://www.who.int/immunization/monitoring_surveillance/global_immunization_data.pdf | access-date= 5 October 2020 | archive-date= 13 April 2020 | archive-url= https://web.archive.org/web/20200413171049/https://www.who.int/immunization/monitoring_surveillance/global_immunization_data.pdf | url-status= live }}</ref> They estimate that 29% of deaths of children under five-years-old in 2013 were vaccine preventable. In other developing parts of the world, they are faced with the challenge of having a decreased availability of resources and vaccinations. Countries such as those in [[Place:Sub-Saharan Africa|Sub-Saharan Africa]] cannot afford to provide the full range of childhood vaccinations.<ref>{{cite journal | vauthors = Ehreth J | title = The global value of vaccination | journal = Vaccine | volume = 21 | issue = 7–8 | pages = 596–600 | date = January 2003 | pmid = 12531324 | doi = 10.1016/S0264-410X(02)00623-0 }}</ref>

===United States===
Vaccines have led to major decreases in the prevalence of infectious diseases in the United States. In 2007, studies regarding the effectiveness of vaccines on mortality or morbidity rates of those exposed to various diseases have shown almost 100% decreases in death rates, and about a 90% decrease in exposure rates.<ref>{{cite journal | vauthors = Roush SW, Murphy TV | title = Historical comparisons of morbidity and mortality for vaccine-preventable diseases in the United States | journal = JAMA | volume = 298 | issue = 18 | pages = 2155–63 | date = November 2007 | pmid = 18000199 | doi = 10.1001/jama.298.18.2155 | doi-access = free }}</ref> This has allowed specific organizations and states to adopt standards for recommended early childhood vaccinations. Lower income families who are unable to otherwise afford vaccinations are supported by these organizations and specific government laws. The Vaccines for Children Program and the Social Security Act are two major players in supporting lower socioeconomic groups.<ref>{{cite web |title=Vaccines for Children Program (VFC) |url=https://www.cdc.gov/vaccines/programs/vfc/index.html |publisher=CDC |access-date=8 December 2019 |date=2 April 2019 |archive-date=1 May 2020 |archive-url=https://web.archive.org/web/20200501175435/https://www.cdc.gov/vaccines/programs/vfc/index.html |url-status=live }}</ref><ref>{{cite web |title=Program for Distribution of Pediatric Vaccines |url=https://www.ssa.gov/OP_Home/ssact/title19/1928.htm |website=Social Security |publisher=U.S. Government |access-date=8 December 2019 |archive-date=30 October 2019 |archive-url=https://web.archive.org/web/20191030185531/https://www.ssa.gov/OP_Home/ssact/title19/1928.htm |url-status=live }}</ref>

In 2000, the CDC declared that measles had been eliminated in the US (defined as no disease transmission for 12 continuous months).<ref>{{Cite web|url=https://www.cdc.gov/measles/about/history.html|title=Measles {{!}} History of Measles {{!}} CDC|date=25 February 2019|website=www.cdc.gov|access-date=28 March 2019|archive-date=6 April 2020|archive-url=https://web.archive.org/web/20200406003814/https://www.cdc.gov/measles/about/history.html|url-status=live}}</ref> However, with the growing anti-vaccine movement, the US has seen a resurgence of certain [[Medicine:Vaccine-preventable diseases|vaccine-preventable diseases]]. The measles virus has now lost its elimination status in the US as the number of measles cases continues to rise in recent years with a total of 17 outbreaks in 2018 and 465 outbreaks in 2019 (as of 4 April 2019).<ref>{{Cite web|url=https://www.cdc.gov/measles/cases-outbreaks.html|title=Measles {{!}} Cases and Outbreaks {{!}} CDC|date=24 March 2019|website=www.cdc.gov|access-date=28 March 2019|archive-date=13 February 2015|archive-url=https://web.archive.org/web/20150213145736/http://www.cdc.gov/measles/cases-outbreaks.html|url-status=live}}</ref>

==History==
[[File:Edward Jenner, testimonial to the efficacy of vaccination. Wellcome L0020705.jpg|thumb|upright=0.8|left|An 1802 testimonial to the efficacy of vaccination, presented to its pioneer, Edward Jenner, and signed by 112 members of the Physical Society, London]]

Before the first vaccinations, in the sense of using [[Medicine:Cowpox|cowpox]] to inoculate people against [[Medicine:Smallpox|smallpox]], people have been inoculated in China and elsewhere, before being copied in the west, by using smallpox, called [[Biology:Variolation|variolation]]. The earliest hints of the practice of variolation for smallpox in China come during the 10th century.<ref name="needham volume 6 part 6 154">{{cite book| vauthors = Needham J |title=Science and Civilisation in China: Volume 6, Biology and Biological Technology, Part 6, Medicine|publisher=Cambridge University Press|year=2000|isbn=9780521632621|page=154}}</ref> The Chinese also practiced the oldest documented use of variolation, which comes from Wan Quan's (1499–1582) Douzhen Xinfa (痘疹心法) of 1549. They implemented a method of "nasal [[Medicine:Insufflation|insufflation]]" administered by blowing powdered smallpox material, usually scabs, up the nostrils. Various insufflation techniques have been recorded throughout the sixteenth and seventeenth centuries within China.<ref name="Williams2010">{{cite book| vauthors = Williams G |title=Angel of Death|publisher=Palgrave Macmillan|year=2010|isbn=978-0-230-27471-6|location=Basingstoke c}}</ref>{{rp|60}} Two reports on the Chinese practice of [[Biology:Inoculation|inoculation]] were received by the Royal Society in London in 1700; one by Martin Lister who received a report by an employee of the East India Company stationed in China and another by Clopton Havers.<ref>{{cite book| vauthors = Silverstein AM |title=A History of Immunology|publisher=Academic Press|year=2009|isbn=9780080919461|edition=2nd|page=293}}</ref> In France, [[Biography:Voltaire|Voltaire]] reports that the Chinese have practiced variolation "these hundred years".

In 1796, Edward Jenner, a doctor in Berkeley in Gloucestershire, England, tested a common theory that a person who had contracted cowpox would be immune from smallpox. To test the theory, he took cowpox vesicles from a milkmaid named Sarah Nelmes with which he infected an eight-year-old boy named James Phipps, and two months later he inoculated the boy with smallpox, and smallpox did not develop. In 1798, Jenner published ''An Inquiry Into the Causes and Effects of the Variolæ Vaccinæ'' which created widespread interest. He distinguished 'true' and 'spurious' cowpox (which did not give the desired effect) and developed an "arm-to-arm" method of propagating the vaccine from the vaccinated individual's pustule. Early attempts at confirmation were confounded by contamination with smallpox, but despite controversy within the medical profession and religious opposition to the use of animal material, by 1801 his report was translated into six languages and over 100,000 people were vaccinated.<ref name="GrossSepkowitz">{{cite journal | vauthors = Gross CP, Sepkowitz KA | title = The myth of the medical breakthrough: smallpox, vaccination, and Jenner reconsidered | journal = International Journal of Infectious Diseases | volume = 3 | issue = 1 | pages = 54–60 | date = July 1998 | pmid = 9831677 | doi = 10.1016/s1201-9712(98)90096-0 | doi-access = free }}</ref> The term ''vaccination'' was coined in 1800 by the surgeon Richard Dunning in his text ''Some observations on vaccination''.<ref>{{Cite web|vauthors=Dunning R|date=1800|publisher=March and Teape|url=https://curiosity.lib.harvard.edu/contagion/catalog/36-990061255320203941|title=Some observations on vaccination, or, The inoculated cow-pox; Some observations on vaccination; Inoculated cow-pox; Observations, & c; Observations, &c|website=Contagion – CURIOSity Digital Collections|language=en|access-date=2 April 2020|archive-date=18 March 2020|archive-url=https://web.archive.org/web/20200318151610/https://curiosity.lib.harvard.edu/contagion/catalog/36-990061255320203941|url-status=live}}</ref>

[[File:Queens_of_Mysore_(detail),_Thomas_Hickey,_1805.jpg|thumb|upright=1.6|Queens of [[History:Kingdom of Mysore|Mysore]]: left, king Krishnaraja Wadiyar III's first wife, Devajammani, right, the king's second wife, also named Devajammani, center: Lakshmi Ammani, the king's grandmother. Thomas Hickey, 1805. The two queens in the painting are thought to advertise vaccination over variolation, as they display the respective traces on their skin: discoloration around the nose and mouth (left, variolation), or a small hidden scar (right, vaccination).<ref>{{cite web |last1=Sethu |first1=Divya |title=How 3 Mysore Queens Became The Face Of A Campaign For The World's First Vaccine |url=https://www.thebetterindia.com/251100/national-vaccination-day-india-smallpox-covid-19-vaccine-awareness-programme-british-history-div200/ |website=The Better India |date=16 March 2021 |access-date=26 October 2022 |archive-date=22 March 2023 |archive-url=https://web.archive.org/web/20230322100108/https://www.thebetterindia.com/251100/national-vaccination-day-india-smallpox-covid-19-vaccine-awareness-programme-british-history-div200/ |url-status=live }}</ref><ref>{{cite web |title=An Indian Queen's "Vaccine Selfie" in Oils |url=https://www.gavi.org/vaccineswork/indian-queens-vaccine-selfie-oils |website=www.gavi.org |language=en |access-date=26 October 2022 |archive-date=15 March 2023 |archive-url=https://web.archive.org/web/20230315005757/https://www.gavi.org/vaccineswork/indian-queens-vaccine-selfie-oils |url-status=live }}</ref><ref>{{cite news |title=The Indian queens who modelled for the world's first vaccine |url=https://www.bbc.com/news/world-asia-india-53944723 |work=BBC News |date=19 September 2020 |access-date=26 October 2022 |archive-date=20 September 2020 |archive-url=https://web.archive.org/web/20200920173003/https://www.bbc.com/news/world-asia-india-53944723 |url-status=live }}</ref>]]
In 1802, the Scottish physician Helenus Scott vaccinated dozens of children in Bombay against smallpox using Jenner's cowpox vaccine.<ref>{{cite book| vauthors = Foege WH |title=House on Fire: The Fight to Eradicate Smallpox|url=https://books.google.com/books?id=ZunWRQ5_2TAC&pg=PA92|year=2011|publisher=University of California Press|isbn=978-0-520-26836-4|page=92}}</ref> In the same year Scott penned a letter to the editor in the ''Bombay Courier'', declaring that "We have it now in our power to communicate the benefits of this important discovery to every part of India, perhaps to China and the whole eastern world".<ref name="Bennett_2016">{{cite book |title=The War Against Smallpox: Edward Jenner and the Global Spread of Vaccination |title-link=War against smallpox: Edward Jenner and the global spread of vaccination |vauthors=Bennett M |publisher=Cambridge University Press |year=2016 |isbn=9780521765671}}</ref>{{rp|243}} Subsequently, vaccination became firmly established in British India. A vaccination campaign was started in the new British colony of Ceylon in 1803. By 1807 the British had vaccinated more than a million Indians and Sri Lankans against smallpox.<ref name = "Bennett_2016" />{{rp|244}} Also in 1803 the Spanish Balmis Expedition launched the first transcontinental effort to vaccinate people against smallpox.<ref>{{Cite web|date=2021-07-27|title=Exhibition tells story of Spanish children used as vaccine fridges in 1803|url=http://www.theguardian.com/world/2021/jul/27/spanish-museum-celebrates-pioneer-who-took-smallpox-vaccine-to-colonies|access-date=2021-07-31|website=the Guardian|language=en|archive-date=3 September 2021|archive-url=https://web.archive.org/web/20210903184520/https://www.theguardian.com/world/2021/jul/27/spanish-museum-celebrates-pioneer-who-took-smallpox-vaccine-to-colonies|url-status=live}}</ref>  Following a smallpox epidemic in 1816 the [[History:Kingdom of Nepal|Kingdom of Nepal]] ordered smallpox vaccine and requested the English veterinarian William Moorcroft to help in launching a vaccination campaign.<ref name = "Bennett_2016" />{{rp|265–266}} In the same year a law was passed in Sweden to require the vaccination of children against smallpox by the age of two. [[Place:Prussia|Prussia]] briefly introduced compulsory vaccination in 1810 and again in the 1920s, but decided against a compulsory vaccination law in 1829. A law on compulsory smallpox vaccination was introduced in the Province of Hanover in the 1820s. In 1826, in [[Place:Kragujevac|Kragujevac]], future prince Mihailo of Serbia was the first person to be vaccinated against smallpox in the principality of Serbia.<ref>{{Cite web|url=https://www.kragujevacke.rs/DRUSTVO/ISTORIJA-VAKCINACIJA-U-SRBIJI/|title=Prvo vakcinisanje u Kragujevcu|access-date=17 May 2021|archive-date=8 March 2022|archive-url=https://web.archive.org/web/20220308184525/https://www.kragujevacke.rs/DRUSTVO/ISTORIJA-VAKCINACIJA-U-SRBIJI/|url-status=live}}</ref> Following a smallpox epidemic in 1837 that caused 40,000 deaths, the British government initiated a concentrated [[Medicine:Vaccination policy|vaccination policy]], starting with the [[Biology:Vaccination Act|Vaccination Act]] of 1840, which provided for universal vaccination and prohibited [[Biology:Variolation|variolation]].<ref name = "Bennett_2016" />{{rp|365}} The Vaccination Act 1853 introduced compulsory smallpox vaccination in England and Wales.<ref name = "Brunton_2008">{{Cite book|title=The Politics of Vaccination: Practice and Policy in England, Wales, Ireland, and Scotland, 1800-1874 | vauthors = Brunton D |publisher=University Rochester Press|year=2008|isbn=9781580460361}}</ref>{{rp|39}} The law followed a severe outbreak of smallpox in 1851 and 1852. It provided that the poor law authorities would continue to dispense vaccination to all free of charge, but that records were to be kept on vaccinated children by the network of births registrars.<ref name = "Brunton_2008" />{{rp|41}} It was accepted at the time, that voluntary vaccination had not reduced smallpox mortality,<ref name = "Brunton_2008" />{{rp|43}} but the Vaccination Act 1853 was so badly implemented that it had little impact on the number of children vaccinated in England and Wales.<ref name = "Brunton_2008" />{{rp|50}}

[[File:Poster for vaccination against smallpox.jpg|thumb|upright=0.8|A 1979 poster from [[Place:Lagos|Lagos, Nigeria]], to promote the worldwide eradication of smallpox<ref name = "Magner_2009">{{Cite book|title=A History of Infectious Diseases and the Microbial World | vauthors = Magner LN |publisher=ABC-CLIO|year=2009|isbn=9780275995058 }}</ref>{{rp|116}}]]
The U.S. Supreme Court upheld compulsory vaccination laws in the 1905 landmark case [[Biology:Jacobson v. Massachusetts|Jacobson v. Massachusetts]], ruling that laws could require vaccination to protect the public from dangerous communicable diseases. However, in practice the U.S. had the lowest rate of vaccination among industrialized nations in the early 20th century. Compulsory vaccination laws began to be enforced in the U.S. after [[Social:World War II|World War II]]. In 1959, the WHO called for the eradication of smallpox worldwide, as smallpox was still endemic in 33 countries. In the 1960s six to eight children died each year in the U.S. from vaccination-related complications. According to the WHO there were in 1966 about 100&nbsp;million cases of smallpox worldwide, causing an estimated two million deaths. In the 1970s there was such a small risk of contracting smallpox that the U.S. Public Health Service recommended for routine smallpox vaccination to be ended. By 1974 the WHO smallpox vaccination program had confined smallpox to parts of {{wipe|Pakistan}}, India, Bangladesh, Ethiopia and Somalia. In 1977 the WHO recorded the last case of smallpox infection acquired outside a laboratory in Somalia. In 1980 the WHO officially declared the world free of smallpox.<ref name = "Magner_2009" />{{rp|115–116}}

In 1974 the WHO adopted the goal of universal vaccination by 1990 to protect children against six preventable infectious diseases: [[Medicine:Measles|measles]], [[Medicine:Poliomyelitis|poliomyelitis]], [[Medicine:Diphtheria|diphtheria]], [[Medicine:Whooping cough|whooping cough]], [[Medicine:Tetanus|tetanus]], and [[Medicine:Tuberculosis|tuberculosis]].<ref name = "Magner_2009" />{{rp|119}} In the 1980s only 20 to 40% of children in developing countries were vaccinated against these six diseases. In wealthy nations the number of measles cases had dropped dramatically after the introduction of the [[Medicine:Measles vaccine|measles vaccine]] in 1963. WHO figures demonstrate that in many countries a decline in measles vaccination leads to a resurgence in measles cases. Measles are so contagious that public health experts believe a vaccination rate of 100% is needed to control the disease.<ref name = "Magner_2009" />{{rp|120}} Despite decades of mass vaccination polio remains a threat in India, Nigeria, Somalia, Niger, Afghanistan, Bangladesh and Indonesia. By 2006 global health experts concluded that the eradication of polio was only possible if the supply of drinking water and [[Engineering:Sanitation|sanitation]] facilities were improved in slums.<ref name="Magner_2009" />{{rp|124}} The deployment of a combined [[Medicine:DPT vaccine|DPT vaccine]] against [[Medicine:Diphtheria|diphtheria]], pertussis (whooping cough), and [[Medicine:Tetanus|tetanus]] in the 1950s was considered a major advancement for public health. But in the course of vaccination campaigns that spanned decades, DPT vaccines became associated with large number of cases with side effects. Despite improved DPT vaccines coming onto the market in the 1990s DPT vaccines became the focus of anti-vaccination campaigns in wealthy nations. As immunization rates fell outbreaks of pertussis increased in many countries.<ref name = "Magner_2009" />{{rp|128}}

In 2000, the Global Alliance for Vaccines and Immunization was established to strengthen routine vaccinations and introduce new and underused vaccines in countries with a per capita GDP of under US$1000.<ref>{{cite journal |vauthors=Jaupart P, Dipple L, Dercon S |date=3 December 2019 |title=Has Gavi lived up to its promise? Quasi-experimental evidence on country immunisation rates and child mortality |journal=BMJ Global Health |volume=3 |issue=4 |page=e001789 |doi=10.1136/bmjgh-2019-001789 |pmc=6936423 |pmid=31908857}}</ref>

UNICEF has reported on the extent to which children missed out on vaccinations from 2020 onwards due to the COVID-19 pandemic. By summer 2023, the organisation described vaccination programs as getting "back on track".<ref>UNICEF UK, ''Child Matters'', Summer 2023, pp. 10-11</ref>

==Vaccination policy==
{{Main|Medicine:Vaccination policy}}
[[File:DTP-Vaccination-rate-by-US-State-and-exemption-status-1.png|thumb|upright=1.2|Vaccination rate by US state, including exemptions allowed by state in 2017]]
To eliminate the risk of [[Medicine:Disease outbreak|outbreaks]] of some diseases, at various times governments and other institutions have employed policies requiring vaccination for all people. For example, an 1853 law required universal vaccination against smallpox in England and Wales, with fines levied on people who did not comply.<ref>{{cite book | vauthors = Brunton D |title=The Politics of Vaccination: Practice and Policy in England, Wales, Ireland, and Scotland, 1800–1874 |date=2008 |publisher=University of Rochester Press |page=39}}</ref> Common contemporary U.S. vaccination policies require that children receive recommended vaccinations before entering public school.<ref>{{cite web |title=State Vaccination Requirements |url=https://www.cdc.gov/vaccines/imz-managers/laws/state-reqs.html |publisher=CDC |access-date=7 December 2019 |date=11 March 2019 |archive-date=2 April 2020 |archive-url=https://web.archive.org/web/20200402194736/https://www.cdc.gov/vaccines/imz-managers/laws/state-reqs.html |url-status=live }}</ref>

Beginning with early vaccination in the nineteenth century, these policies were resisted by a variety of groups, collectively called antivaccinationists, who object on scientific, ethical, political, medical safety, [[Medicine:Vaccination and religion|religious]], and other grounds.<ref>{{cite journal | vauthors = Tolley K |title=School Vaccination Wars |journal=History of Education Quarterly |date=May 2019 |volume=59 |issue=2 |pages=161–194 |doi=10.1017/heq.2019.3|doi-access=free }}</ref> Common objections are that vaccinations do not work, that compulsory vaccination constitutes excessive government intervention in personal matters, or that the proposed vaccinations are not sufficiently safe.<ref name="wolfesharp">{{cite journal | vauthors = Wolfe RM, Sharp LK | title = Anti-vaccinationists past and present | journal = BMJ | volume = 325 | issue = 7361 | pages = 430–2 | date = August 2002 | pmid = 12193361 | pmc = 1123944 | doi = 10.1136/bmj.325.7361.430 }}</ref> Many modern vaccination policies allow exemptions for people who have compromised immune systems, allergies to the components used in vaccinations or strongly held objections.<ref>{{cite journal | vauthors = Salmon DA, Teret SP, MacIntyre CR, Salisbury D, Burgess MA, Halsey NA | s2cid = 19344405 | title = Compulsory vaccination and conscientious or philosophical exemptions: past, present, and future | journal = Lancet | volume = 367 | issue = 9508 | pages = 436–42 | date = February 2006 | pmid = 16458770 | doi = 10.1016/S0140-6736(06)68144-0 }}</ref>

In countries with limited financial resources, limited vaccination coverage results in greater morbidity and mortality due to infectious disease.<ref>{{cite journal | vauthors = Mhatre SL, Schryer-Roy AM | title = The fallacy of coverage: uncovering disparities to improve immunization rates through evidence. Results from the Canadian International Immunization Initiative Phase 2 – Operational Research Grants | journal = BMC International Health and Human Rights | volume = 9 | issue = S1 | pages = S1 | date = October 2009 | pmid = 19828053 | pmc = 3226229 | doi = 10.1186/1472-698X-9-S1-S1 | doi-access = free }}</ref> More affluent countries are able to subsidize vaccinations for at-risk groups, resulting in more comprehensive and effective coverage. In Australia, for example, the Government subsidizes vaccinations for seniors and indigenous Australians.<ref>{{Cite web|url=http://www.nps.org.au/consumers/publications/medicines_talk/medicinestalk_no._32_summer_2009/time_to_think_about_vaccinations_again  |title=Time to think about vaccinations again? |archive-url=https://web.archive.org/web/20110727175547/http://www.nps.org.au/consumers/publications/medicines_talk/medicinestalk_no._32_summer_2009/time_to_think_about_vaccinations_again |archive-date=27 July 2011 |url-status=dead |work=Medicines Talk (No. 32 Summer 2009)|publisher=[[Organization:NPS MedicineWise|NPS MedicineWise]] |location=Sydney, Australia |date=1 February 2010}}</ref>

Public Health Law Research, an independent US based organization, reported in 2009 that there is insufficient evidence to assess the effectiveness of requiring vaccinations as a condition for specified jobs as a means of reducing incidence of specific diseases among particularly vulnerable populations;<ref>{{cite web |url=http://publichealthlawresearch.org/product/laws-and-policies-requiring-specified-vaccinations-among-high-risk-populations |title=Laws and Policies Requiring Specified Vaccinations among High Risk Populations |publisher=Public Health Law Research |date=7 December 2009 |access-date=19 November 2014 |archive-date=18 November 2017 |archive-url=https://web.archive.org/web/20171118222128/http://publichealthlawresearch.org/product/laws-and-policies-requiring-specified-vaccinations-among-high-risk-populations |url-status=live }}</ref> that there is sufficient evidence supporting the effectiveness of requiring vaccinations as a condition for attending child care facilities and schools;<ref>{{cite web |url=http://publichealthlawresearch.org/product/vaccination-requirements-child-care-school-and-college-attendance |title=Vaccination Requirements for Child Care, School and College Attendance |publisher=Public Health Law Research |date=12 July 2009 |access-date=19 November 2014 |archive-date=18 November 2017 |archive-url=https://web.archive.org/web/20171118222300/http://publichealthlawresearch.org/product/vaccination-requirements-child-care-school-and-college-attendance |url-status=live }}</ref> and that there is strong evidence supporting the effectiveness of standing orders, which allow healthcare workers without prescription authority to administer vaccine as a public health intervention.<ref>{{cite web |url=http://publichealthlawresearch.org/product/standing-orders-vaccination |title=Standing Orders for Vaccination |publisher=Public Health Law Research |date=12 July 2009 |access-date=8 January 2014 |archive-date=18 November 2017 |archive-url=https://web.archive.org/web/20171118222356/http://publichealthlawresearch.org/product/standing-orders-vaccination |url-status=live }}</ref>

=== Fractional dose vaccination ===
Fractional dose vaccination reduces the dose of a vaccine to allow more individuals to be vaccinated with a given vaccine stock, trading societal benefit for individual protection. Based on the [[Nonlinear system|nonlinearity]] properties of many vaccines, it is effective in poverty diseases<ref>{{Cite journal|date=2012-01-05|title=Intradermal fractional dose inactivated polio vaccine: A review of the literature|url=https://www.sciencedirect.com/science/article/pii/S0264410X11017853|journal=Vaccine|language=en|volume=30|issue=2|pages=121–125|doi=10.1016/j.vaccine.2011.11.018|issn=0264-410X|last1=Nelson|first1=Katherine S.|last2=Janssen|first2=Julia M.|last3=Troy|first3=Stephanie B.|last4=Maldonado|first4=Yvonne|pmid=22100886|access-date=18 August 2021|archive-date=26 January 2022|archive-url=https://web.archive.org/web/20220126062155/https://www.sciencedirect.com/science/article/pii/S0264410X11017853|url-status=live}}</ref> and promises benefits in pandemic waves, e.g. in [[Medicine:COVID-19|COVID-19]],<ref>{{Cite journal|vauthors=Hunziker P|date=2021-07-24|title=Personalized-dose Covid-19 vaccination in a wave of virus Variants of Concern: Trading individual efficacy for societal benefit|url=https://precisionnanomedicine.com/article/26101-personalized-dose-covid-19-vaccination-in-a-wave-of-virus-variants-of-concern-trading-individual-efficacy-for-societal-benefit|journal=Precision Nanomedicine|language=en|volume=4|issue=3|pages=805–820|doi=10.33218/001c.26101|doi-access=free|access-date=18 August 2021|archive-date=9 October 2021|archive-url=https://web.archive.org/web/20211009194402/https://precisionnanomedicine.com/article/26101-personalized-dose-covid-19-vaccination-in-a-wave-of-virus-variants-of-concern-trading-individual-efficacy-for-societal-benefit|url-status=live}}</ref> when vaccine supply is limited.

=== Litigation ===
Allegations of vaccine injuries in recent decades have appeared in litigation in the U.S. Some families have won substantial awards from sympathetic juries, even though most public health officials have said that the claims of injuries were unfounded.<ref name="Sugarman">{{cite journal | vauthors = Sugarman SD | title = Cases in vaccine court—legal battles over vaccines and autism | journal = The New England Journal of Medicine | volume = 357 | issue = 13 | pages = 1275–7 | date = September 2007 | pmid = 17898095 | doi = 10.1056/NEJMp078168 | doi-access = free }}</ref> In response, several vaccine makers stopped production, which the US government believed could be a threat to public health, so laws were passed to shield manufacturers from [[Social:Legal liability|liabilities]] stemming from vaccine injury claims.<ref name="Sugarman" /> The safety and side effects of multiple vaccines have been tested to uphold the viability of vaccines as a barrier against disease. The [[Medicine:Influenza vaccine|influenza vaccine]] was tested in controlled trials and proven to have negligible side effects equal to that of a [[Medicine:Placebo|placebo]].<ref>{{cite journal | vauthors = Nichol KL, Margolis KL, Lind A, Murdoch M, McFadden R, Hauge M, Magnan S, Drake M | title = Side effects associated with influenza vaccination in healthy working adults. A randomized, placebo-controlled trial | journal = Archives of Internal Medicine | volume = 156 | issue = 14 | pages = 1546–50 | date = July 1996 | pmid = 8687262 | doi = 10.1001/archinte.1996.00440130090009 }}</ref> Some concerns from families might have arisen from social beliefs and norms that cause them to [[Unsolved:Vaccine hesitancy|mistrust or refuse vaccinations]], contributing to this discrepancy in side effects that were unfounded.<ref>{{cite journal | vauthors = Oraby T, Thampi V, Bauch CT | title = The influence of social norms on the dynamics of vaccinating behaviour for paediatric infectious diseases | journal = Proceedings. Biological Sciences | volume = 281 | issue = 1780 | pages = 20133172 | date = April 2014 | pmid = 24523276 | pmc = 4078885 | doi = 10.1098/rspb.2013.3172 }}</ref>

===Opposition===
[[File:Global trend in believing vaccines are not safe.png|thumb|upright=1.75|Global survey across 67 countries responding to the question: "Overall I think vaccines are safe". This image depicts the distribution of responses that replied "Strongly disagree" or "Tend to disagree" with the previous statement.<ref>{{cite journal | vauthors = Larson HJ, de Figueiredo A, Xiahong Z, Schulz WS, Verger P, Johnston IG, Cook AR, Jones NS | title = The State of Vaccine Confidence 2016: Global Insights Through a 67-Country Survey | journal = eBioMedicine | volume = 12 | pages = 295–301 | date = October 2016 | pmid = 27658738 | pmc = 5078590 | doi = 10.1016/j.ebiom.2016.08.042 }}</ref>]]
{{main|Unsolved:Vaccine hesitancy}}
Opposition to vaccination, from a wide array of vaccine critics, has existed since the earliest vaccination campaigns.<ref name=wolfesharp/> It is widely accepted that the benefits of preventing serious illness and death from [[Medicine:Infectious disease|infectious disease]]s greatly outweigh the risks of rare serious adverse effects following [[Biology:Immunization|immunization]].<ref name="BH">{{cite journal | vauthors = Bonhoeffer J, Heininger U | s2cid = 40669829 | title = Adverse events following immunization: perception and evidence | journal = Current Opinion in Infectious Diseases | volume = 20 | issue = 3 | pages = 237–46 | date = June 2007 | pmid = 17471032 | doi = 10.1097/QCO.0b013e32811ebfb0 }}</ref> Some studies have claimed to show that current vaccine schedules increase infant mortality and hospitalization rates;<ref>{{cite journal | vauthors = Miller NZ, Goldman GS | title = Infant mortality rates regressed against number of vaccine doses routinely given: is there a biochemical or synergistic toxicity? | journal = Human & Experimental Toxicology | volume = 30 | issue = 9 | pages = 1420–8 | date = September 2011 | pmid = 21543527 | pmc = 3170075 | doi = 10.1177/0960327111407644 }}</ref><ref>{{cite journal | vauthors = Goldman GS, Miller NZ | title = Relative trends in hospitalizations and mortality among infants by the number of vaccine doses and age, based on the Vaccine Adverse Event Reporting System (VAERS), 1990–2010 | journal = Human & Experimental Toxicology | volume = 31 | issue = 10 | pages = 1012–21 | date = October 2012 | pmid = 22531966 | pmc = 3547435 | doi = 10.1177/0960327112440111 }}</ref> those studies, however, are correlational in nature and therefore cannot demonstrate causal effects, and the studies have also been criticized for [[Cherry picking|cherry picking]] the comparisons they report, for ignoring historical trends that support an opposing conclusion, and for counting vaccines in a manner that is "completely arbitrary and riddled with mistakes".<ref name="Science Mom">{{cite web |last1=Science Mom |first1=Catherina |title=Infant mortality and vaccines |url=http://justthevax.blogspot.com/2011/05/oh-goodness-here-i-wanted-to-go-to-bed.html |website=Just The Vax |publisher=Blogspot.com |access-date=10 October 2019 |date=9 May 2011 |archive-date=10 October 2019 |archive-url=https://web.archive.org/web/20191010150149/http://justthevax.blogspot.com/2011/05/oh-goodness-here-i-wanted-to-go-to-bed.html |url-status=live }}</ref><ref name="Gorski">{{Cite journal |last1=Miller |first1=N. |last2=Goldman |first2=G. |date=2011 |title=Infant mortality rates regressed against number of vaccine doses routinely given: Is there a biochemical or synergistic toxicity? |url=https://scienceblogs.com/insolence/2011/05/16/vaccines-and-infant-mortality-rates |journal=Human & Experimental Toxicology |volume=30 |issue=9 |pages=1420–1428 |doi=10.1177/0960327111407644 |issn=0960-3271 |access-date=10 October 2019 |archive-date=26 January 2022 |archive-url=https://web.archive.org/web/20220126065905/https://scienceblogs.com/insolence/2011/05/16/vaccines-and-infant-mortality-rates |url-status=live |doi-access=free |pmc=3170075 }}</ref>

Various disputes have arisen over the morality, ethics, [[Chemistry:Efficacy|effectiveness]], and safety of vaccination. Some vaccination critics say that vaccines are ineffective against disease<ref name="Halvorsen">{{cite book | vauthors = Halvorsen R |title=The Truth about Vaccines |publisher=Gibson Square |year=2007 |isbn=978-1-903933-92-3}}</ref> or that vaccine safety studies are inadequate.<ref name="Halvorsen" /> Some religious groups do not allow vaccination,<ref>{{cite journal | vauthors = Sinal SH, Cabinum-Foeller E, Socolar R | s2cid = 29738930 | title = Religion and medical neglect | journal = Southern Medical Journal | volume = 101 | issue = 7 | pages = 703–6 | date = July 2008 | pmid = 18580731 | doi = 10.1097/SMJ.0b013e31817997c9 }}</ref> and some political groups oppose mandatory vaccination on the grounds of [[Philosophy:Liberty|individual liberty]].<ref name=wolfesharp/> In response, concern has been raised that spreading [[Social:Disinformation|unfounded information]] about the medical risks of vaccines increases rates of life-threatening infections, not only in the children whose parents refused vaccinations, but also in those who cannot be vaccinated due to age or immunodeficiency, who could contract infections from unvaccinated carriers (see [[Medicine:Herd immunity|herd immunity]]).<ref>{{cite journal | vauthors = Omer SB, Salmon DA, Orenstein WA, deHart MP, Halsey N | title = Vaccine refusal, mandatory immunization, and the risks of vaccine-preventable diseases | journal = The New England Journal of Medicine | volume = 360 | issue = 19 | pages = 1981–8 | date = May 2009 | pmid = 19420367 | doi = 10.1056/NEJMsa0806477 | s2cid = 5353949 | doi-access = free }}</ref> Some parents believe vaccinations cause [[Medicine:Autism|autism]], although there is no scientific evidence to support this idea.<ref>{{cite journal | vauthors = Gross L | title = A broken trust: lessons from the vaccine--autism wars | journal = PLOS Biology | volume = 7 | issue = 5 | pages = e1000114 | date = May 2009 | pmid = 19478850 | pmc = 2682483 | doi = 10.1371/journal.pbio.1000114 | doi-access = free }}</ref> In 2011, [[Biography:Andrew Wakefield|Andrew Wakefield]], a leading proponent of the theory that MMR vaccine causes autism, was found to have been financially motivated to falsify research data and was subsequently stripped of his [[Medicine:Medical license|medical license]].<ref>{{cite news |url=http://www.cnn.com/2011/HEALTH/01/05/autism.vaccines/index.html |title=Retracted autism study an 'elaborate fraud,' British journal finds |publisher=CNN.com |date=6 January 2011 |access-date=26 April 2013 |archive-date=4 January 2018 |archive-url=https://web.archive.org/web/20180104085313/http://www.cnn.com/2011/HEALTH/01/05/autism.vaccines/index.html |url-status=live }}</ref> In the United States people who refuse vaccines for non-medical reasons have made up a large percentage of the cases of [[Medicine:Measles|measles]], and subsequent cases of permanent hearing loss and death caused by the disease.<ref>{{cite journal | vauthors = Phadke VK, Bednarczyk RA, Salmon DA, Omer SB | title = Association Between Vaccine Refusal and Vaccine-Preventable Diseases in the United States: A Review of Measles and Pertussis | journal = JAMA | volume = 315 | issue = 11 | pages = 1149–58 | date = March 2016 | pmid = 26978210 | pmc = 5007135 | doi = 10.1001/jama.2016.1353 }}</ref>

Many parents do not vaccinate their children because they feel that diseases are no longer present due to vaccination.<ref>{{cite web|url=https://www.who.int/immunization/newsroom/events/immunization_week/2012/further_information/en/|archive-url=https://web.archive.org/web/20130921020026/http://www.who.int/immunization/newsroom/events/immunization_week/2012/further_information/en/|url-status=dead|archive-date=21 September 2013|title=WHO – World Immunization Week 2012|website=who.int}}</ref> This is a false assumption, since diseases held in check by immunization programs can and do still return if immunization is dropped.  These pathogens could possibly infect vaccinated people, due to the pathogen's ability to mutate when it is able to live in unvaccinated hosts.<ref>{{Cite web |url=https://io9.gizmodo.com/how-poor-vaccination-rates-can-help-viruses-beat-the-va-1492482862 |title=Why anti-vaxxers might be creating a world of more dangerous viruses |vauthors=Inglis-Arkell E |website=io9 |date=January 2014 |language=en-US |access-date=10 June 2019 |archive-date=13 July 2019 |archive-url=https://web.archive.org/web/20190713192201/https://io9.gizmodo.com/how-poor-vaccination-rates-can-help-viruses-beat-the-va-1492482862 |url-status=live }}</ref><ref>{{Cite web|url=https://www.contagionlive.com/news/pertussis-and-other-diseases-could-return-if-vaccination-rates-lag|title=Pertussis and Other Diseases Could Return If Vaccination Rates Lag|website=ContagionLive|access-date=10 June 2019|archive-date=26 March 2019|archive-url=https://web.archive.org/web/20190326195203/https://www.contagionlive.com/news/pertussis-and-other-diseases-could-return-if-vaccination-rates-lag|url-status=live}}</ref>

====Vaccination and autism====
{{Main|Unsolved:Vaccines and autism}}

The notion of a connection between vaccines and autism originated in a 1998 paper published in ''The Lancet'' whose lead author was the physician [[Biography:Andrew Wakefield|Andrew Wakefield]]. His study concluded that eight of the 12 patients, ages 3 years to 10 years, developed behavioral symptoms consistent with autism following the [[Medicine:MMR vaccine|MMR vaccine]] (an immunization against [[Medicine:Measles|measles]], [[Medicine:Mumps|mumps]], and [[Medicine:Rubella|rubella]]).<ref name="Wakefield">{{cite journal | vauthors = Wakefield AJ, Murch SH, Anthony A, Linnell J, Casson DM, Malik M, Berelowitz M, Dhillon AP, Thomson MA, Harvey P, Valentine A, Davies SE, Walker-Smith JA | s2cid = 439791 | title = Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children | journal = Lancet | volume = 351 | issue = 9103 | pages = 637–41 | date = February 1998 | pmid = 9500320 | doi = 10.1016/S0140-6736(97)11096-0 | url = http://briandeer.com/mmr/lancet-paper.htm |  access-date = 5 February 2012 | archive-date = 27 September 2007 | archive-url = https://web.archive.org/web/20070927010149/http://briandeer.com/mmr/lancet-paper.htm | url-status = live }}{{Retracted|intentional=yes}}</ref> The article was widely criticized for lack of scientific rigor and it was proven that Wakefield falsified data in the article.<ref name="Wakefield" /> In 2004, 10 of the original 12 co-authors (not including Wakefield) published a [[Retraction in academic publishing|retraction]] of the article and stated the following: "We wish to make it clear that in this paper no causal link was established between MMR vaccine and autism as the data were insufficient."<ref>{{cite journal | vauthors = Murch SH, Anthony A, Casson DH, Malik M, Berelowitz M, Dhillon AP, Thomson MA, Valentine A, Davies SE, Walker-Smith JA | s2cid = 5128036 | title = Retraction of an interpretation | journal = Lancet | volume = 363 | issue = 9411 | pages = 750 | date = March 2004 | pmid = 15016483 | doi = 10.1016/S0140-6736(04)15715-2 }}</ref> In 2010, ''The Lancet'' officially retracted the article, stating that several elements of the article were incorrect, including falsified data and protocols. The article has sparked a much greater anti-vaccination movement, particularly in the United States, and even though the article was shown to be fraudulent and was heavily retracted, one in four parents still believe that vaccines can cause autism.<ref>{{cite journal | vauthors = Daley MF, Glanz JM | title = Straight talk about vaccination | journal = Scientific American | volume = 305 | issue = 3 | pages = 32–34 | date = September 2011 | pmid = 21870438 | doi = 10.1038/scientificamerican0911-32 | bibcode = 2011SciAm.305b..32D }}</ref>

To date, all validated and definitive studies have shown that there is no correlation between vaccines and autism.<ref>{{Cite web|url=https://www.cdc.gov/vaccinesafety/concerns/autism.html|title=Vaccines Do Not Cause Autism Concerns Vaccine Safety CDC|date=6 February 2019|website=www.cdc.gov|access-date=22 March 2019|archive-date=16 March 2017|archive-url=https://web.archive.org/web/20170316105455/https://www.cdc.gov/vaccinesafety/concerns/autism.html|url-status=live}}</ref> One of the studies published in 2015 confirms there is no link between [[Social:MMR vaccine and autism|autism and the MMR vaccine]]. Infants were given a health plan, that included an MMR vaccine, and were continuously studied until they reached five years old. There was no link between the vaccine and children who had a normally developed sibling or a sibling that had autism making them a higher risk for developing autism themselves.<ref>{{cite journal | vauthors = Jain A, Marshall J, Buikema A, Bancroft T, Kelly JP, Newschaffer CJ | title = Autism occurrence by MMR vaccine status among US children with older siblings with and without autism | journal = JAMA | volume = 313 | issue = 15 | pages = 1534–40 | date = April 2015 | pmid = 25898051 | doi = 10.1001/jama.2015.3077 | doi-access = free }}</ref>

It can be difficult to correct the memory of humans when wrong information is received prior to correct information. Even though there is much evidence to go against the Wakefield study and retractions were published by most of the co-authors, many people continue to believe and base decisions on the study as it still lingers in their memory. Studies and research are being conducted to determine effective ways to correct misinformation in the public memory.<ref>{{cite journal | vauthors = Pluviano S, Watt C, Della Sala S | title = Misinformation lingers in memory: Failure of three pro-vaccination strategies | journal = PLOS ONE | volume = 12 | issue = 7 | pages = e0181640 | date = 27 July 2017 | pmid = 28749996 | pmc = 5547702 | doi = 10.1371/journal.pone.0181640 | bibcode = 2017PLoSO..1281640P | doi-access = free }}</ref>

==Routes of administration==
A vaccine administration may be oral, by injection (intramuscular, intradermal, subcutaneous), by puncture, [[Medicine:Transdermal|transdermal]] or intranasal.<ref>{{cite book | vauthors = Plotkin SA | title = Mass Vaccination: Global Aspects – Progress and Obstacles (Current Topics in Microbiology & Immunology) | publisher = Springer-Verlag Berlin and Heidelberg GmbH & Co. K | year = 2006 | isbn = 978-3-540-29382-8 }}</ref> Several recent clinical trials have aimed to deliver the vaccines via mucosal surfaces to be up-taken by the common mucosal immunity system, thus avoiding the need for injections.<ref>{{cite journal | vauthors = Fujkuyama Y, Tokuhara D, Kataoka K, Gilbert RS, McGhee JR, Yuki Y, Kiyono H, Fujihashi K | title = Novel vaccine development strategies for inducing mucosal immunity | journal = Expert Review of Vaccines | volume = 11 | issue = 3 | pages = 367–79 | date = March 2012 | pmid = 22380827 | pmc = 3315788 | doi = 10.1586/erv.11.196 }}</ref>

== Economics of vaccination ==
Health is often used as one of the metrics for determining the economic prosperity of a country. This is because healthier individuals are generally better suited to contributing to the economic development of a country than the sick.<ref name="ReferenceA">{{cite journal | vauthors = Quilici S, Smith R, Signorelli C | title = Role of vaccination in economic growth | journal = Journal of Market Access & Health Policy | volume = 3 | pages = 27044 | date = 12 August 2015 | pmid = 27123174 | pmc = 4802686 | doi = 10.3402/jmahp.v3.27044 }}</ref> There are many reasons for this. For instance, a person who is vaccinated for influenza not only protects themselves from the risk of [[Medicine:Influenza|influenza]], but simultaneously also prevents themselves from infecting those around them.<ref name=":0">{{Cite book|date=10 December 2003|title=Financing Vaccines in the 21st Century|url=https://www.nap.edu/read/10782/chapter/2#10|doi=10.17226/10782|pmid=25057673|isbn=978-0-309-08979-1|author1=Institute of Medicine|author2=Board on Health Care Services|author3=Committee on the Evaluation of Vaccine Purchase Financing in the United States|access-date=6 February 2019|archive-date=20 March 2022|archive-url=https://web.archive.org/web/20220320141817/https://www.nap.edu/read/10782/chapter/2#10|url-status=live}}</ref> This leads to a healthier society, which allows individuals to be more economically productive. Children are consequently able to attend school more often and have been shown to do better academically. Similarly, adults are able to work more often, more efficiently, and more effectively.<ref name="ReferenceA"/><ref>{{Cite news|url=https://econlife.com/2015/02/economic-positive-externalities-of-vaccination/|title=The Economic Side of Vaccines' Positive Externalities|date=24 February 2015|work=Econlife|access-date=7 September 2018|archive-date=8 September 2018|archive-url=https://web.archive.org/web/20180908094224/https://econlife.com/2015/02/economic-positive-externalities-of-vaccination/|url-status=live}}</ref>

=== Costs and benefits ===

On the whole, vaccinations induce a net benefit to society. Vaccines are often noted for their high [[Finance:Return on investment|Return on investment]] (ROI) values, especially when considering the long-term effects.<ref>{{cite journal | vauthors = Carroll S, Rojas AJ, Glenngård AH, Marin C | title = Vaccination: short- to long-term benefits from investment | journal = Journal of Market Access & Health Policy | volume = 3 | pages = 27279 | date = 12 August 2015 | pmid = 27123171 | pmc = 4802682 | doi = 10.3402/jmahp.v3.27279 }}</ref> Some vaccines have much higher ROI values than others. Studies have shown that the ratios of vaccination benefits to costs can differ substantially—from 27:1 for diphtheria/pertussis, to 13.5:1 for measles, 4.76:1 for varicella, and 0.68–1.1 : 1 for pneumococcal conjugate.<ref name=":0" /> Some governments choose to subsidize the costs of vaccines, due to some of the high ROI values attributed to vaccinations. The United States subsidizes over half of all vaccines for children, which costs between $400 and $600 each. Although most children do get vaccinated, the adult population of the USA is still below the recommended immunization levels. Many factors can be attributed to this issue. Many adults who have other health conditions are unable to be safely immunized, whereas others opt not to be immunized for the sake of private financial benefits. Many Americans are underinsured, and, as such, are required to pay for vaccines out-of-pocket. Others are responsible for paying high deductibles and co-pays. Although vaccinations usually induce long-term economic benefits, many governments struggle to pay the high short-term costs associated with labor and production. Consequently, many countries neglect to provide such services.<ref name=":0" />

According to a 2021 paper, vaccinations against [[Biology:Haemophilus influenzae|haemophilus influenzae type b]], [[Medicine:Hepatitis B|hepatitis B]], [[Medicine:Human papillomavirus infection|human papillomavirus]], [[Medicine:Japanese encephalitis|Japanese encephalitis]], [[Medicine:Measles|measles]], [[Biology:Neisseria meningitidis|neisseria meningitidis serogroup A]], [[Biology:Rotavirus|rotavirus]], [[Medicine:Rubella|rubella]], [[Biology:Streptococcus pneumoniae|streptococcus pneumoniae]], and [[Medicine:Yellow fever|yellow fever]] have prevented an estimated 50 million deaths from 2000 to 2019.<ref name=":7">{{Cite journal|last1=Toor|first1=Jaspreet|last2=Echeverria-Londono|first2=Susy|last3=Li|first3=Xiang|last4=Abbas|first4=Kaja|last5=Carter|first5=Emily D|last6=Clapham|first6=Hannah E|last7=Clark|first7=Andrew|last8=de Villiers|first8=Margaret J|last9=Eilertson|first9=Kirsten|last10=Ferrari|first10=Matthew|last11=Gamkrelidze|first11=Ivane|date=2021-07-13|editor-last=Stanley|editor-first=Margaret|editor2-last=Harper|editor2-first=Diane M|editor3-last=Soldan|editor3-first=Kate|title=Lives saved with vaccination for 10 pathogens across 112 countries in a pre-COVID-19 world|journal=[[Biology:ELife|eLife]]|volume=10|pages=e67635|doi=10.7554/eLife.67635|pmid=34253291 |pmc=8277373 |issn=2050-084X |doi-access=free }}</ref> The paper "represents the largest assessment of vaccine impact before COVID-19-related disruptions".<ref name=":7" /> According to a June 2022 study, [[Medicine:COVID-19 vaccine|COVID{{nbhyph}}19 vaccinations]] prevented an additional 14.4 to 19.8 million deaths in 185 countries and territories from 8 December 2020 to 8 December 2021.<ref>{{Cite journal |vauthors=Watson OJ, Barnsley G, Toor J, Hogan AB, Winskill P, Ghani AC |date=June 2022 |title=Global impact of the first year of COVID-19 vaccination: a mathematical modelling study |journal=[[Biology:The Lancet Infectious Diseases|The Lancet Infectious Diseases]] |volume=22 |issue=9 |pages=1293–1302 |doi=10.1016/s1473-3099(22)00320-6 |pmc=9225255 |pmid=35753318 |doi-access=free |title-link=doi}}</ref><ref>{{Cite web |date=24 June 2022 |title=COVID-19 vaccines saved nearly 20 million lives in a year, study says |url=https://www.cbsnews.com/news/covid-19-vaccine-saved-nearly-20-million-lives-in-a-year-study-says/ |url-status=live |archive-url=https://web.archive.org/web/20220629025146/https://www.cbsnews.com/news/covid-19-vaccine-saved-nearly-20-million-lives-in-a-year-study-says/ |archive-date=29 June 2022 |access-date=27 June 2022 |website=CBS News}}</ref>

They estimated that it would cost between $2.8&nbsp;billion and $3.7&nbsp;billion to develop at least one vaccine for each of them. This should be set against the potential cost of an outbreak. The 2003 SARS outbreak in East Asia cost $54&nbsp;billion.<ref>{{cite news |title=Scientists have estimated the cost of stopping 11 diseases that could kill millions in a pandemic |url=https://www.vox.com/future-perfect/2018/10/22/17999676/vaccine-ebola-pandemic-disease-zika-epidemic-sars |access-date=2 December 2018 |publisher=Vox |date=22 October 2018 |archive-date=6 November 2018 |archive-url=https://web.archive.org/web/20181106173404/https://www.vox.com/future-perfect/2018/10/22/17999676/vaccine-ebola-pandemic-disease-zika-epidemic-sars |url-status=live }}</ref>

[[Game theory]] uses [[Utility|utility functions]] to model costs and benefits, which may include financial and non-financial costs and benefits.  In recent years, it has been argued that game theory can effectively be used to model vaccine uptake in societies. Researchers have used game theory for this purpose to analyse vaccination uptake in the context of diseases such as influenza and measles.<ref>{{cite journal | vauthors = Chang SL, Piraveenan M, Pattison P, Prokopenko M | title = Game theoretic modelling of infectious disease dynamics and intervention methods: a review | journal = Journal of Biological Dynamics | volume = 14 | issue = 1 | pages = 57–89 | date = December 2020 | pmid = 31996099 | doi = 10.1080/17513758.2020.1720322 | s2cid = 58004680 | arxiv = 1901.04143 }}</ref>

==Gallery==
<gallery perrow="6">
File:Jenner phipps 01.jpg|Dr Jenner performing his first vaccination on James Phipps, a boy of age 8. 14 May 1796. Painting by Ernest Board (early 20th century)
File:The cow pock.jpg|James Gillray's ''The Cow-Pock—or—the Wonderful Effects of the New Inoculation!'', an 1802 caricature of vaccinated patients who feared it would make them sprout cowlike appendages
File:Londre wellcome institute boilly vaccinee.jpg|''La vaccine'' or ''Le préjugé vaincu'' by Louis-Léopold Boilly, 1807
File:A doctor vaccinating a small girl, other girls with loosened Wellcome V0016682.jpg|''A doctor vaccinating a small girl, other girls with loosened blouses wait their turn apprehensively'' by Lance Calkin
File:'Serum straight from the horse'., inoculation caricature Wellcome L0009827.jpg|German caricature showing [[Biography:Emil von Behring|von Behring]] extracting the serum with a tap
File:The history of vaccination seen from an economic point of vi Wellcome V0011691.jpg|''Les Malheurs de la Vaccine'' (The history of vaccination seen from an economic point of view: A pharmacy up for sale; an outmoded inoculist selling his premises; Jenner, to the left, pursues a skeleton with a lancet)
</gallery>

== See also ==
{{div col|colwidth=18em}}
* [[Biology:Antitoxin|Antitoxin]]
* [[Biology:Correlates of immunity|Correlates of immunity]]
* [[Medicine:COVID-19 vaccine|COVID-19 vaccine]]
* [[Biology:DNA vaccination|DNA vaccination]]
* [[Biology:Feline vaccination|Feline vaccination]]
* [[Biology:H5N1 clinical trials|H5N1 clinical trials]]
* [[Medicine:Immunization during pregnancy|Immunization during pregnancy]]
* [[Medicine:List of vaccine topics|List of vaccine topics]]
* Misinformation related to vaccination
* [[Medicine:Vaccination and religion|Vaccination and religion]]
* [[Biology:Vaccination of dogs|Vaccination of dogs]]
* [[Medicine:Vaccinator|Vaccinator]]
* [[Vaccine trial]]
* World Immunization Week
{{div col end}}

== References ==
{{reflist|refs=
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<ref name="Blakemore">{{cite web | vauthors = Blakemore E |title=How an African Slave in Boston Helped Save Generations from Smallpox |url=https://www.history.com/news/smallpox-vaccine-onesimus-slave-cotton-mather |website=HISTORY |access-date=21 October 2019 |language=en |date=1 February 2019}}</ref>
-->
}}

== Further reading ==
{{refbegin}}
* {{cite web | vauthors = Carroll AE | url = https://www.nytimes.com/2015/09/18/upshot/not-up-for-debate-the-science-behind-vaccination.html | title = Not Up for Debate: The Science Behind Vaccination | work = The New York Times | date = 17 September 2015 | access-date = 6 February 2019 | archive-date = 7 February 2019 | archive-url = https://web.archive.org/web/20190207091929/https://www.nytimes.com/2015/09/18/upshot/not-up-for-debate-the-science-behind-vaccination.html | url-status = live }}
* {{cite web|vauthors=Cole JP, Swendiman KS|url=https://fas.org/sgp/crs/misc/RS21414.pdf|title=Mandatory Vaccinations: Precedent and Current Laws|publisher=[[Social:Congressional Research Service|Congressional Research Service]]|date=21 May 2014|access-date=31 January 2020|archive-date=9 August 2021|archive-url=https://web.archive.org/web/20210809044625/https://fas.org/sgp/crs/misc/RS21414.pdf|url-status=live}}
* {{cite book | vauthors = Largent MA |title=Vaccine: The Debate in Modern America |publisher=Johns Hopkins University Press |location=Baltimore |year=2012 |isbn=978-1-4214-0607-7 }}
* {{cite book | last=Offit | first=Paul A. | title=Vaccinated | publisher=Harper Collins | date=2007-06-12 | isbn=978-0-06-122795-0}}
* {{cite book | vauthors = Williams G |title=Angel of Death |year=2010 |publisher=Palgrave Macmillan |location=Basingstoke |isbn=978-0230274716 |ref=none}}
* {{cite book | vauthors = Walloch KL | title = The Antivaccine Heresy: Jacobson v. Massachusetts and the Troubled History of Compulsory Vaccination in the United States | publisher = University of Rochester Press | date = 2015 | page = xii }}
{{refend}}

== External links ==
{{Library resources box |by=no |onlinebooks=no |others=yes lcheading=Vaccination}}
* [https://www.niaid.nih.gov/about/vrc U.S. government Vaccine Research Center]: Information regarding preventive vaccine research studies
* [http://vaccines.org/ The Vaccine Page] links to resources in many countries.
* [https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/323504/8807_PHE_Complete_Immunisation_Schedule_A4_2014_11.pdf "The complete routine immunisation schedule from summer 2014". Published by the UK Department of Health.] (PDF)
* [https://web.archive.org/web/20060331015359/http://www.cdc.gov/nip/ National Immunization Program], US Centers for Disease Control
* "[https://www.cdc.gov/vaccinesafety/ Vaccine Safety]"  – US Centers for Disease Control
* "[https://web.archive.org/web/20140228045539/http://www.cdc.gov/vaccines/pubs/vacc-timeline.htm Vaccines Timeline]" – Centers for Disease Control and Prevention
* [http://www.immunize.org/ Immunize.org] – Immunization Action Coalition' (nonprofit working to increase immunization rates)
* [https://www.who.int/immunization/en/ WHO.int] – 'Immunizations, vaccines and biologicals: Towards a World free of Vaccine Preventable Diseases', [[Organization:World Health Organization|World Health Organization]] (WHO's global vaccination campaign website)
* [http://ec.europa.eu/health-eu/care_for_me/vaccinations/index_en.htm Health-EU Portal] Vaccinations in the EU
* [http://www.historyofvaccines.org History of Vaccines] Medical education site from the College of Physicians of Philadelphia, the oldest medical professional society in the US
* [http://www.aap.org/en-us/about-the-aap/aap-press-room/aap-press-room-media-center/pages/AAP-Pressroom-Photos.aspx Images of vaccine-preventable diseases]
* [https://www.bbc.co.uk/programmes/p003c19q Immunisation], BBC Radio 4 discussion with Nadja Durbach, Chris Dye & Sanjoy Bhattacharya (''In Our Time'', 20 April 2006)
{{Vaccines}}


[[Category:Biotechnology]]

{{Sourceattribution|Vaccination}}