26. Development of a Safer Smallpox Vaccine From Cowpox
Variolation did wonders to stave off smallpox – but only among the variolated, a minority of the population. Voltaire estimated that in his day, about 60% of the population came down with smallpox. Of those, about 20% died and many of those who survived were left blind or with disfiguring pockmarks. The fight against smallpox took a major leap in 1796, when British doctor Edward Jenner invented the smallpox vaccine. Unlike variolation, which used smallpox material for inoculation, Jenner used the mild cowpox virus, which infects cattle. Inoculation with cowpox conferred immunity against the deadlier and more dangerous smallpox.
Jenner tested his theory on his gardener’s son, whom he inoculated with cowpox, then deliberately gave him a dose of smallpox, which did not take. Further tests on 23 more patients, including Jenner’s own eleven-month-old son, confirmed the effectiveness of cowpox to inoculate against smallpox. Death rates from inoculation via smallpox variolation took a nosedive from a typical 0.5-2.0% to virtually none when cowpox vaccination was used. Widespread vaccination with Jenner’s methods began in the early 1800s, and as seen below, were met with vehement and often dumb criticism from the era’s anti-vaxxers.
