Who created the first successful vaccine against yellow fever in the 1930s?

Max Theiler created the first successful vaccine against yellow fever in the 1930s. At the Rockefeller Foundation, Theiler repeatedly cultured yellow fever virus in mouse embryos and selected a weakened strain known as 17D. The attenuated virus could stimulate immunity without causing typical yellow fever in vaccinated people.

The 17D vaccine became one of the most successful vaccines in medical history and remains important for preventing yellow fever. Yellow fever is a mosquito-borne viral disease that can cause fever, jaundice, bleeding, and organ failure. The vaccine is especially important for people living in or traveling to risk areas.

Theiler received the 1951 Nobel Prize in Physiology or Medicine for his discoveries concerning yellow fever and how to combat it. A common mix-up is to confuse yellow fever with malaria: both are mosquito-borne, but yellow fever is caused by a virus, while malaria is caused by Plasmodium parasites. The 17D strain is still used in modern yellow-fever vaccination.