The Birth of Vaccination in the 1700s

In 1796, British physician Edward Jenner conducted the first successful test of a smallpox vaccine by inoculating a young boy with a less severe, cowpox-related disease. He documented his findings to the Royal Society of Medicine, but his paper was rejected.

Undeterred, Jenner tested the vaccine on 22 additional subjects and published his findings in a pamphlet in 1798, which received mixed reactions. However, interest surged when another doctor, Henry Cline, replicated Jenner's success.

At that time, there was no official advisory committee to assess vaccine safety, allowing Jenner to distribute the vaccine freely. By 1800, the vaccine had spread across Europe, and in 1802, Dr. Benjamin Waterhouse conducted a public vaccination trial in Boston, successfully inoculating 19 volunteers.

By 1980, smallpox became the first infectious disease to be completely eradicated through vaccination, thanks to improved needle technology and the World Health Organization's mass vaccination initiatives.

This long-term effort laid the groundwork for future vaccines and public health successes, paving the way for present-day efforts to combat the coronavirus pandemic.

Polio Vaccine Development

Research into polio immunity began at the Rockefeller Institute for Medical Research in the early 20th century. In 1910, Simon Flexner observed that monkeys who survived polio developed antibodies.

However, early trials of polio vaccines on humans in 1935 produced disastrous outcomes, resulting in several deaths and numerous cases of paralysis.

It wasn't until 1952 that Jonas Salk developed a vaccine using inactivated polio virus, which showed promising results in early trials. Salk warned that extensive testing was necessary to confirm the vaccine's safety and efficacy, countering overly optimistic media reports.

By 1955, Salk's vaccine was found to be 80–90% effective in a large-scale clinical trial involving 1.3 million children. The US government approved the vaccine, but a suspension of the rollout occurred when some batches contained live virus, leading to over 260 cases of polio.

Vaccination resumed in the fall of 1955, and the Pan American Health Organization declared polio eradicated in the Americas by 1994.

Typhoid Fever Vaccine Research

In the 1890s, several groups were researching a vaccine for typhoid fever, with contributions from Richard Pfeiffer, Wilhelm Kolle in Germany, and Almroth Wright in the UK.

Wright tested his vaccine in 1896 on Indian medical officers, himself, and British soldiers. Following successful trials, the vaccine was rolled out to the British Army in 1899, immunizing nearly 15,000 soldiers and reducing typhoid fever rates.

The US Army mandated vaccinations in 1911, and the typhoid vaccine became available to the American public in 1914. Currently, vaccination is recommended primarily for travelers to endemic regions, with campaigns still ongoing in parts of South Asia and Africa.

Yellow Fever Vaccine Development

In 1931, Max Theiler from Harvard demonstrated that previously infected monkeys or humans could protect mice from yellow fever. He developed the first safe and effective yellow fever vaccine, named 17D, in 1936.

Theiler published his human trial results in 1937, leading to quick approval and mass production of the vaccine, which became the standard. He later received a Nobel Prize for his work.

By 1961, mass vaccination campaigns nearly eradicated yellow fever in some countries, although outbreaks persisted in others, particularly in Africa.

Influenza Vaccine Evolution

British scientists Wilson Smith, Christopher Andrewes, and Patrick Laidlaw isolated the influenza virus in 1933 and began antibody research in ferrets.

Jonas Salk and Thomas Francis created the first influenza A vaccine in 1938, and in 1940, they developed a two-component vaccine that included influenza B by 1942.

Initially produced for military personnel in 1944, the combined vaccine was licensed for civilian use in 1945 after successful trials on military recruits and college students.

However, the 1947 flu outbreak highlighted the need for new vaccines each year due to the emergence of new strains. The WHO established its first Influenza Centre in London in 1948, and similar centers continue to research new vaccines worldwide.

Measles, Mumps, and Rubella Vaccine Development

American physician Thomas Peebles isolated the measles virus in February 1954 during an outbreak near Boston. His team tested an early version of the vaccine on children with intellectual and physical disabilities in 1958, finding it too potent.

After several reformulations, John Enders licensed a safe and effective measles vaccine in 1963. Maurice Hilleman developed a more refined vaccine in 1968, combining it with mumps and rubella vaccines to create the MMR vaccine in 1971.

The CDC aimed to eliminate measles in the US with routine vaccinations starting in 1978, achieving success in 2000. However, international cases have led to small outbreaks in the 21st century.

Hepatitis B Vaccine Innovations

Four years after discovering the hepatitis B virus, Baruch Blumberg developed the first vaccine in 1969 using an antigen found in Australia, winning a Nobel Prize for his research.

In 1981, the FDA approved a more advanced vaccine derived from the blood of hepatitis B-positive donors, but it was discontinued in 1990 amid AIDS fears.

In 1986, researchers created a vaccine from genetically engineered DNA, which is still in use today, as it does not contain blood products and cannot transmit the virus.

Chickenpox Vaccine Breakthroughs

In 1974, Michiaki Takahashi isolated the “Oka” strain of varicella from a young boy in Japan and developed a live attenuated chickenpox vaccine, testing it on 23 hospitalized children. All developed antibodies without illness during a ward outbreak.

Clinical trials continued until 1986 when the vaccine was approved for voluntary use. The chickenpox vaccine was licensed in the US in 1995, becoming the first routine varicella vaccination for children.

Swine Flu Vaccine Development

The first human case of the new influenza A H1N1 virus was reported on April 15, 2009. The CDC announced ongoing vaccine research on April 21.

Clinical trials for H1N1 vaccine candidates began on July 22, with the FDA approving four vaccines by September 15. The US placed its first vaccine orders two weeks later, officially launching its H1N1 vaccination campaign in October.

Initial shortages delayed widespread availability until December, but studies on the vaccine's long-term safety continued throughout the year.

COVID-19 Vaccine Response

In early December 2019, the WHO was notified of an unusual pneumonia outbreak in Wuhan, China. It was later identified as COVID-19, caused by the new coronavirus, SARS-CoV-2, as reported by Chinese officials on January 7.

On March 16, 2020, just five days after the WHO declared a pandemic, Moderna initiated safety trials for its coronavirus vaccine. Other companies quickly followed suit, with over 50 potential vaccine candidates expected to be in human trials by year-end.

In November, both Moderna and Pfizer reported encouraging preliminary trial results, and they planned to seek emergency use authorization from the FDA as soon as safety data were finalized.

If approved, vaccinations could begin in late 2020 or early 2021, prioritizing frontline workers and vulnerable groups, while the general public may have to wait until summer for broader access.