Fifth Era of Vaccinology

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A recent commentary (A Desmond, P Offit. NEJM 2021; 384: 1081-1083. Full text: On the Shoulders of Giants — From Jenner’s Cowpox to mRNA Covid Vaccines) succinctly describes the five major vaccine-related advances. The link also provides access to an audio interview with Dr. Offit

1st Advance: In 1796, Edward Jenner “found that an animal virus (cowpox) could protect against disease caused by a human virus (smallpox)… Jenner’s work ultimately led to the eradication of a disease that is estimated to have killed more than 300 million people in the 20th century”

2nd Advance: In 1885, Louis Pasteur developed an inactivated virus vaccine for rabies. This has led to the development of many other inactivated vaccines, including the influenza vaccine.

3rd Advance: In 1937, Max Theiler attenuated yellow fever virus by means of serial passage in mouse and chicken embryos. This has led to the development of numerous attenuated vaccines to prevent polio (Sabin, 1960s), measles (1963), mumps (1967), rubella (1969), varicella (1995), and rotavirus (2008).

4th Advance: In 1980, Stanford biochemists Richard Mulligan and Paul Berg developed recombinant DNA technology which led to vaccines containing purified surface proteins. This led to the hepatitis B virus (1986), human papillomavirus (2006), and influenza virus (2013) vaccines.

Some of the notable improvements related to vaccines:

  • In U.S., the incidence of polio dropped from 29,000 cases in 1955 to elimination
  • In U.S., during the “2019–2020 influenza season, the influenza vaccine prevented an estimated 7.52 million infections, 3.69 million medical visits, 105,000 hospitalizations, and 6300 deaths”
  • In U.S., the measles vaccine has nearly eliminated a virus that previously caused 2 million to 3 million infections, 50,000 hospitalizations, and 500 deaths every year
  • In U.S., “since the hepatitis B virus vaccine started being routinely recommended for newborns in the early 1990s, rates of hepatitis B virus infection among children younger than 10 years have fallen from about 18,000 per year to nearly zero”
  • Globally, “between 2000 and 2018, roughly 23 million measles deaths were prevented by vaccination…Live attenuated rotavirus vaccines are countering a virus that once killed more than 500,000 infants and young children each year”

5th Advance: In 2020 “with the recent authorization of mRNA vaccines, we have entered the fifth era of vaccinology. This class of vaccines doesn’t contain viral proteins; rather, these vaccines use mRNA, DNA, or viral vectors that provide instructions to cells on how to make such proteins. The SARS-CoV-2 pandemic will be an important test of whether these new platforms can fulfill their promise of creating safe, effective, and scalable vaccines more quickly than traditional methods.”

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