Mayo Clinic Proceedings Home

Max Theiler—Nobel Laureate for Yellow Fever Vaccine

      The 1951 Nobel Prize for medicine or physiology was awarded to South African physician and microbiologist Max Theiler for his discoveries concerning yellow fever and its treatment. His work not only resulted in the development of a vaccine against yellow fever but also showed how vaccines could be developed against other diseases.
      Theiler was born on June 30, 1899, in Pretoria, South Africa. He was the youngest of 4 children of Swiss-born parents. His father, Sir Arnold Theiler (1867–1936), was a prominent veterinarian who was director of the South African government veterinary service. Theiler's early education was obtained at Rhodes University College in Grahamstown, South Africa, and at the University of Cape Town Medical School, which he entered in 1916. After 2 years, he left South Africa to enroll at St Thomas' Hospital in London and in the London School of Hygiene and Tropical Medicine. He received his MD degree in 1922.
      Theiler left England in 1922 to join the Department of Tropical Medicine at Harvard Medical School in Boston, Mass. Although he spent the rest of his life in the United States, he retained his South African citizenship. His early work at Harvard Medical School concerned amebic dysentery, but he soon became interested in the study of yellow fever. In 1881, a Cuban physician, Carlos Finlay (1833–1915), hypothesized that yellow fever was spread by the bite of a mosquito. However, his work was largely ignored by the medical community until 1900, when American surgeon Walter Reed (1851–1902) established the connection between mosquitoes and the disease, proving that Finlay's theory was correct. Reed sought to control the disease by killing the mosquitoes. In 1911, investigators discovered that mosquitoes could carry the disease and transmit it from monkey to monkey and from monkeys to humans. Thus, it became obvious that a vaccine was needed to control the disease.
      In 1930, Theiler discovered that the common mouse was susceptible to yellow fever. This provided a new research model that was less expensive and more available than monkeys. He also noted that passing the disease from mouse to mouse weakened the yellow fever virus. The yellow fever virus he cultivated in mice became the basis of 2 vaccines. One was a weakened strain used in the 1930s and 1940s by the French government to protect the residents of French territories in western Africa. The second (and improved) version was grown in chicken embryos and was not only more effective but also easier to mass-produce. By 1937, it was widely used.
      In 1930, Theiler left Harvard Medical School to join the Rockefeller Institute for Medical Research (now Rockefeller University) in New York City, where he continued his research and improved the vaccine. He became director of the institute in 1951. In 1964, he left New York City to become professor of epidemiology and microbiology at Yale University in New Haven, Conn. He retired from Yale University in 1967 and became associated with the Rockefeller Foundation, where he remained until 1972. He died of lung cancer on August 11, 1972, at the age of 73 years.
      Theiler was honored philatelically by Gambia in 1989 and by South Africa in 1996.