According to lore, Jenner was a country doctor-albeit a well-educated one-who heard a rumor that the cowpox virus could provide immunity to smallpox. Investigating the theory, Jenner endured the disbelief of colleagues-not to mention the stench of dairy farms-before proving his point.
But prove it he did. In a now-famous 1796 experiment, Jenner scratched the arm of eight-year-old James Phipps, infecting the boy with cowpox pus taken from a milkmaid carrying the virus. Two months later, he scratched James again, this time adding a touch of smallpox. The rest, as they say, is history: James was fine. A smallpox vaccine-and the field of vaccinology-was launched. Today, smallpox has been eradicated. In a similar vein, the pioneering work of researchers like Albert Sabin and Jonas Salk roughly 150 years later led to vaccines against polio, now wiped from the Western Hemisphere.
Since 1980, 14 new or improved vaccines have been released, ...
