Theiler, Max (1899–1972)

South African-born US microbiologist who was awarded a Nobel Prize for Physiology or Medicine in 1951 for his discovery of a vaccine against yellow fever. He also conducted research into various other diseases, including Weil's disease and poliomyelitis.

Theiler was born in Pretoria and began his studies at the University of Cape Town, South Africa, completing them in the UK at St Thomas's Hospital, London, and the London School of Hygiene and Tropical Medicine. In 1922 he emigrated to the USA. From 1930 to 1964 he worked at the Rockefeller Institute for Medical Research (now Rockefeller University), New York City, becoming director of the Virus Laboratory there in 1950. He ended his career as professor at Yale.

Theiler used albino mice in his work on yellow fever, and eventually combined the mouse-adapted viral strain with serum from the blood of people who had recovered from yellow fever and injected the mixture into humans. This produced immunity without affecting the kidneys and liver, and was the first safe vaccine against yellow fever. It was used from 1935 in Brazil.

However, human serum containing antibodies against yellow fever is difficult to obtain. Theiler therefore began culturing the virus in chick embryos, and in 1937 he developed vaccine 17-D, still the main form of protection against yellow fever.