Max Theiler health at the Yale School of Medicine and the School of Public Health from 1964 to 1967. After passing the yellow fever virus through laboratory mice, Theiler found that the weakened virus conferred immunity on rhesus macaques. The stage was set for Theiler to develop a vaccine against the disease. Theiler first devised a test for the efficacy of experimental vaccines. In his test, sera from vaccinated human subjects were injected into mice to see if they protected the mice against yellow fever virus. This "mouse protection test" was used with variations as a measure of immunity until after World
Max Theiler moved to the United States to do research at the Harvard University School of Tropical Medicine. He lived and worked in that nation the rest of his life. In 1930, he moved to the Rockefeller Foundation in New York, becoming director of the Virus Laboratory. Theiler was born in Pretoria, then the capital of the South African Republic (now South Africa); his father Arnold Theiler was a veterinary bacteriologist. He attended Pretoria Boys High School, Rhodes University College, and University of Cape Town Medical School, graduating in 1918. He left South Africa for London to study at St Thomas's Hospital