The measles vaccine
Who
Samuel L. Katz, an American Jewish pediatrician, with John Enders and their team
When
1963
Where
Boston, United States
Measles killed millions of children a year worldwide before there was a vaccine. In John Enders's laboratory in Boston, the young paediatrician Samuel Katz did the work of weakening the virus strain until it would provoke immunity without disease, and ran the field trials; the vaccine was licensed in 1963. Katz, an American Jewish physician, spent the rest of his life pressing for it to reach the children who had no access to it. Measles deaths have fallen by more than nine tenths since.
Part of “The Gifts of the Jews” — verified Jewish contributions to the world, with sources.