The word “vaccine” originates from the word vacca, which is Latin for … cow.
In 1796, English physician Edward Jenner noticed one of the greatest miracles in the history of medical science: milkmaids who had previously been infected with cowpox (a vaccinia virus) showed no symptoms of smallpox after being exposed to the virus through so-called “intentional variolation.”
In a variolation, a doctor transferred smallpox pustules from a sick patient into a healthy patient because for reasons no one at the time understood, a “variolated patient” typically developed only a mild case of smallpox while still gaining lifelong immunity.
This exceptional fact was already known in a simpler disguise for a long time in the medieval farmer community: “by milking cows, one was protected from human smallpox.” The miracle was hidden in the details: some of these cows had cowpox, and Jenner discovered the very underlying mechanism: treating a patient with a less virulent pathogen triggers an immune response, without causing the actual disease.
Since 1900 more than 200 million people died from smallpox, but thanks to a global vaccination campaign in 1977, the disease was essentially eradicated. Thanks to Edward Jenner —
And the cow’s udder.
SOURCES: the footnote site. For the images: Cow’s udder with smallpox, Wellcome Collection. (© Public domain) and Johannes Vermeer, Public domain, via Wikimedia Commons.