History of Vaccination in Timeline

Vaccination is the administration of a vaccine to stimulate the immune system and develop immunity against a disease. Vaccines contain weakened, live, or killed microorganisms, or their components. By triggering adaptive immunity, they prevent illness from infectious diseases. Widespread vaccination leads to herd immunity, protecting vulnerable individuals. The effectiveness of vaccination is well-established, with it being the most effective method for preventing infectious diseases. Vaccination has led to the eradication of smallpox and the elimination of diseases like polio and tetanus in many regions. The WHO estimates that vaccines prevent 3.5–5 million deaths annually, and a study estimates that vaccination prevented 154 million deaths between 1974 and 2024. However, vaccine hesitancy has contributed to rising cases of some diseases due to low vaccination rates.

1905: U.S. Supreme Court upholds compulsory vaccination laws

In 1905, the U.S. Supreme Court upheld compulsory vaccination laws in the landmark case Jacobson v. Massachusetts, ruling that laws could require vaccination to protect the public from dangerous communicable diseases.

1959: WHO calls for smallpox eradication

In 1959, the WHO called for the eradication of smallpox worldwide, as smallpox was still endemic in 33 countries.

1963: Introduction of the measles vaccine

In wealthy nations the number of measles cases had dropped dramatically after the introduction of the measles vaccine in 1963.

1966: Smallpox cases worldwide

According to the WHO, in 1966 there were about 100 million cases of smallpox worldwide, causing an estimated two million deaths.

1974: Smallpox confined to parts of Asia and Africa

By 1974, the WHO smallpox vaccination program had confined smallpox to parts of Pakistan, India, Bangladesh, Ethiopia and Somalia.

1974: Vaccination prevents deaths

In 1974, a WHO-funded study by The Lancet estimates that, during the 50-year period starting in 1974, vaccination prevented 154 million deaths, including 146 million among children under age 5.

1974: WHO adopts goal of universal vaccination

In 1974, the WHO adopted the goal of universal vaccination by 1990 to protect children against six preventable infectious diseases: measles, poliomyelitis, diphtheria, whooping cough, tetanus, and tuberculosis.

1977: Last case of smallpox infection acquired outside a laboratory

In 1977, the WHO recorded the last case of smallpox infection acquired outside a laboratory in Somalia.

1979: Smallpox eradicated

In 1979, smallpox was finally eradicated, after killing an estimated 300–500 million people in the 20th century.

1980: WHO declares the world free of smallpox

In 1980, the WHO officially declared the world free of smallpox.

1990: Vaccination rates in developing countries

By 1990, only 20 to 40% of children in developing countries were vaccinated against six diseases.

1998: Andrew Wakefield's paper published

In 1998, a paper led by Andrew Wakefield was published which concluded that eight of the twelve patients developed behavioral symptoms consistent with autism following the administration of the MMR vaccine. The article was widely criticized for lack of scientific rigor and it was proven that Wakefield falsified data in the article.

2000: Estimated start date of death prevention by vaccinations

According to a 2021 paper, vaccinations against haemophilus influenzae type b, hepatitis B, human papillomavirus, Japanese encephalitis, measles, neisseria meningitidis serogroup A, rotavirus, rubella, streptococcus pneumoniae, and yellow fever have prevented an estimated 50 million deaths from 2000 to 2019. The paper "represents the largest assessment of vaccine impact before COVID-19-related disruptions".

2000: Global Alliance for Vaccines and Immunization established

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$1,000.

2001: Thimerosal removed from US childhood vaccines

In 2001, thimerosal was removed from childhood vaccines in the United States as a precaution, even though evidence supports the safety and efficacy of thimerosal in vaccines.

2003: SARS Outbreak Costs

In 2003, the SARS outbreak in East Asia resulted in an economic cost of $54 billion.

2004: Co-authors retract Wakefield's article

In 2004, 10 of the original 12 co-authors (not including Wakefield) published a 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."

2006: Eradication of polio depends on sanitation facilities

By 2006, global health experts concluded that the eradication of polio was only possible if the supply of drinking water and sanitation facilities were improved in slums.

2007: Studies on vaccine effectiveness in the United States

In 2007, studies regarding the effectiveness of vaccines on mortality or morbidity rates of those exposed to various diseases found almost 100% decreases in death rates, and about a 90% decrease in exposure rates in the United States.

2009: Adverse events reported for Pandemrix

In 2009, Pandemrix, a vaccine for the H1N1 pandemic given to around 31 million people, was found to have a higher level of adverse events than alternative vaccines, resulting in legal action. 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.

2009: Public Health Law Research report on vaccination effectiveness

In 2009, Public Health Law Research reported on the effectiveness of vaccination requirements for jobs, childcare facilities, schools, and standing orders for healthcare workers.

2010: The Lancet officially retracts Wakefield's article

In 2010, The Lancet officially retracted Wakefield's article, stating that several elements of the article were incorrect, including falsified data and protocols.

2011: Andrew Wakefield stripped of medical license

In 2011, Andrew Wakefield, a leading proponent of the theory that the MMR vaccine causes autism, was found to have been financially motivated to falsify research data and was subsequently stripped of his medical license.

2013: Vaccine preventable deaths

In 2013, the WHO estimated that 29% of deaths of children under five-years-old were vaccine preventable.

2015: Study confirms no link between MMR vaccine and autism

In 2015, one of the studies confirms there is no link between 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.

2017: Dengvaxia suspended in Philippines

In 2017, a mass vaccination program in the Philippines was suspended after Dengvaxia, the only approved vaccine for Dengue fever, was found to increase the risk of hospitalization for Dengue fever by 1.58 times in children of 9 years or younger.

2019: Estimated end date of death prevention by vaccinations

December 2020: Start date of COVID-19 vaccination impact study

According to a June 2022 study, COVID‑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.

2020: Children missed vaccinations due to COVID-19

UNICEF reported on the extent to which children missed out on vaccinations from 2020 onwards due to the COVID-19 pandemic.

December 2021: End date of COVID-19 vaccination impact study

According to a June 2022 study, COVID‑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.

2021: Vaccinations Prevented 50 million deaths

June 2022: COVID-19 vaccinations prevented additional deaths

According to a June 2022 study, COVID‑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.

2022: Children missing vaccination

In 2022, UNICEF reported on the extent to which children missed out on vaccinations from 2020 onwards due to the COVID-19 pandemic.

2023: Vaccination programs getting back on track

By summer 2023, UNICEF described vaccination programs as getting "back on track".

2024: WHO/UNICEF report on childhood vaccination

In 2024, a WHO/UNICEF report found "the number of children who received three doses of the vaccine against diphtheria, tetanus and pertussis (DTP) in 2023 – a key marker for global immunization coverage – stalled at 84% (108 million). However, the number of children who did not receive a single dose of the vaccine increased from 13.9 million in 2022 to 14.5 million in 2023. More than half of unvaccinated children live in the 31 countries with fragile, conflict-affected and vulnerable settings."