11 Vaccine Pioneers You Should Know

From primitive inoculation techniques to using DNA and mRNA technology, vaccines for the deadliest diseases have come a long way in the past few centuries. Today, people all over the world are alive thanks to these colossal strides in public health. Here are 11 vaccine innovators you should know.

1. Onesimus // Smallpox

Onesimus, an enslaved African man, introduced the concept of variolation (a primitive method of immunizing against variola, the smallpox virus) to the Puritans in colonial Boston. In the early 1700s, while still in West Africa, Onesimus had undergone an unusual medical experience: He had pus from an infected person rubbed into an open wound on his arm to ward off disease. This technique was employed in Africa, Turkey, and China to inoculate healthy individuals against serious infections. When brought to Boston, Onesimus shared this knowledge with his enslaver, Cotton Mather, who later advocated variolation during the smallpox epidemic in 1721 [PDF], saving numerous Bostonians from the deadly virus.

2. Edward Jenner // Smallpox

By the 18th century, many European physicians practiced variolation against smallpox. Jenner, an observant English physician, noted that dairy workers infected with cowpox (an animal virus that was not fatal to humans) also showed resistance to infection with smallpox (a human virus that was often fatal). In May 1796, Jenner swabbed material from a cowpox sore on Sarah Nelms, a milkmaid, and inoculated 8-year-old James Phipps. The boy felt sick for several days after the procedure, then recovered. Two months later, Jenner exposed Phipps to pus from a smallpox sore—and Phipps remained healthy, demonstrating a safer way to build immunity against the deadlier disease. Jenner coined the term vaccination, derived from vacca, Latin for “cow” (differentiating it from variolation, the smallpox-based procedure).

3. Louis Pasteur // Rabies

Louis Pasteur, known for inventing pasteurization (heating foods to kill pathogens), also played a key role in the development of rabies vaccines. In the 1880s, concerned that rabies was spreading through Paris’s population of stray dogs, vets sent Pasteur tissue samples from dogs who died of the disease. Pasteur experimented by injecting infectious material from the tissue directly into rabbits’ brains to study the immediate viral effects. Eventually, he discovered that drying the infected tissue weakened the virus. He produced a vaccine by attenuating the virus in rabbits, making it less virulent. This vaccine successfully prevented rabies in dogs and humans.

4. Max Theiler // Yellow Fever

Theiler discovered that yellow fever virus (which causes a tropical illness marked by gastrointestinal bleeding and liver failure) could be transmitted to mice. That made his experiments to develop a vaccine for yellow fever much easier and cheaper, since he had been using more expensive monkeys in his research. Theiler eventually developed two varieties of yellow fever vaccine. One was a weakened strain used in the 1930s and 1940s to protect residents in West Africa. The second version was grown in chicken embryos; It was more effective and easier to produce, leading to its widespread use by 1937. In 1951, Theiler won the Nobel Prize in Medicine for this work.

5. Thomas Francis // Influenza

Francis, an American microbiologist, made salient contributions towards our understanding of the influenza virus and, subsequently, protection from it. By analyzing respiratory secretions and serum samples from symptomatic children, he was able to scrutinize the virus’s effect on the human respiratory lining. His team developed a vaccine effective against both influenza A and B, first used successfully during World War II in the early 1940s.

6. Jonas Salk // Polio

Jonas Salk’s creation of a vaccine against poliovirus (which can cause neurological symptoms, including paralysis) rendered him a national champion. Contrary to his peers, Salk believed that a “killed-virus” vaccine would be just as effective, and possibly safer, than a “live-virus” vaccine. He formulated a method of deactivating the virus with formaldehyde to destroy its reproductive ability. Salk’s vaccine deceived the immune system into making antibodies against the virus. Salk had full faith in his invention, testing it on his entire family before its approval in 1955.

7. Albert Sabin // Polio

Salk’s competitor, Albert Sabin, introduced an oral polio vaccine in the 1960s. This was a “live” vaccine made by weakening the poliovirus (which attacks the gastrointestinal tract first, and then the nervous system). Sabin’s oral vaccine was not only easier to distribute and administer, but was also cheaper to produce, so it's not surprising that it replaced Salk’s injected vaccine by the early 1960s. Because polio epidemics typically occurred in the summer months, when poliovirus contaminated ponds and lakes, Sabin became known as “the doctor who gave summer back to children.”

8. Maurice Hilleman // Measles and More

Maurice Hilleman, an American microbiologist who specialized in vaccinology, developed more than 40 vaccines during his long career at the pharmaceutical company Merck. He helped develop vaccines for MMR (measles, mumps, rubella), Hepatitis A, Hepatitis B, chicken pox, and others. Many are now recommended for children as part of their routine health care.

9. Richard Mulligan & Paul Berg // Recombinant DNA Technology

These two Stanford biochemists pioneered recombinant DNA technology for vaccine creation—a way to recombine DNA segments to create a new “recombinant” molecule with unique functions. They performed experiments that involved transferring bacterial (E. coli) genes into monkey cells, essentially causing mammalian cells to produce a bacterial protein. This recombinant DNA technology was used to produce hepatitis B vaccine in 1986, HPV vaccine in 2006, and the influenza vaccine in 2013.

10. Katalin Karikó // mRNA Technology

A brilliant Hungarian scientist, Karikó has focused her research on messenger RNA—the genetic liaison that helps translate genetic codes into protein. Despite skepticism from the scientific establishment, Karikó remained steadfast in her conviction that mRNA could herald a revolution in vaccine development. She collaborated with her then-colleague Drew Weissman, a researcher at the University of Pennsylvania, to harness the power of mRNA vaccines. This new type of vaccine teaches our cells how to make a protein (or even a piece of the protein) that triggers an immune response and produces antibodies to protect us from infection. Karikó and Weissman collaborated with Pfizer and BioNTech to produce its COVID-19 vaccine using this technology.

11. Kizzmekia Corbett // COVID-19

Kizzmekia Corbett, an immunologist at NIH’s National Institute of Allergy and Infectious Diseases’ Vaccine Research Center, collaborated with Moderna to develop its mRNA-based vaccine against COVID-19. Her work focuses on the ways coronaviruses infect their hosts and devises vaccine strategies that are “fast, reliable, and universal,” she said in a lecture at NIH last December. Corbett is also dedicated to alleviating vaccine hesitancy and often speaks to communities of color about the science behind the COVID-19 vaccines.