Max Theiler Nobel Prize in Physiology or Medicine, 1951 Date of Birth: 30.01.1899 Country: USA

1. Biography of Max Theiler
2. Research on Yellow Fever
3. Career at Rockefeller Foundation and Vaccine Development
4. Personal Life and Achievements

Biography of Max Theiler

Max Theiler, a South African bacteriologist, was born in Pretoria and was the younger of two sons of Emma (Jeggi) and Arnold Theiler, who were Swiss. His father, a renowned veterinarian, served as the head of the South African state veterinary service. Encouraged by his father to pursue a medical career, Theiler enrolled in a two-year medical course at the University of Cape Town in 1916. He then went to London, where he studied at St. Thomas' Hospital Medical School and the London School of Hygiene and Tropical Medicine, both branches of the University of London. After obtaining his medical degree in 1922, Theiler became an assistant in the Department of Tropical Medicine at Harvard Medical School. His initial work at Harvard focused on amoebic dysentery and the controlled use of sodoku (a disease transmitted by rat bites) for therapeutic purposes, similar to the use of Julius Wagner-Jauregg's malaria fever therapy for the treatment of syphilis. However, Theiler soon became interested in yellow fever.

Research on Yellow Fever

Yellow fever is an acute viral disease found in countries in Africa and America. Its mortality rate often exceeds 10 percent, and even today, the disease remains incurable. During the construction of the Panama Canal, the members of the yellow fever commission, including Walter Reed and William Gorgas, discovered that a specific species of mosquito was the carrier of this disease. Based on Reed's research in 1916, the Rockefeller Foundation developed a program to eliminate yellow fever. The implementation of such measures was prompted by the belief among medical experts that ships passing through the canal would contribute to the transmission of yellow fever from the Caribbean Sea to Asia. However, the predicted disaster did not occur because immunity to dengue fever is cross-protective against yellow fever. Nevertheless, the Rockefeller program seemed very reasonable at the time.

Based on the findings of the yellow fever commission, scientists concluded that this disease only affects humans and can be eradicated by either destroying the mosquito population or creating a vaccine. Since the latter seemed more likely, the main focus became fundamental research on the disease and its causative agent. In 1919, Japanese researcher Hideyo Noguchi reported that he had isolated the bacteria responsible for the onset of yellow fever. By the mid-1920s, other scientists had successfully infected laboratory animals with the causative agent of this disease, which was considered a significant achievement. In 1926, Theiler and his colleague Andrew Sellards provided compelling evidence that yellow fever is caused by a filterable virus, not bacteria. The following year, researchers from the Rockefeller Foundation succeeded in infecting rhesus monkeys by injecting them with blood from yellow fever patients. Continuing his work at Harvard, Theiler managed to infect mice by introducing the virus directly into their brains, rather than subcutaneously as other researchers had done. This was an important step because using mice, which are significantly less expensive and more convenient to work with than monkeys, expedited the study of yellow fever.

Career at Rockefeller Foundation and Vaccine Development

In 1930, Theiler left Harvard and joined the International Health Division of the Rockefeller Foundation in New York. Within a year, he improved the mouse protection test, in which mice were injected with a mixture of yellow fever virus and human serum. The survival of mice indicated that the serum neutralized the virus and that the donor serum was immune. This test allowed for the first accurate assessment of the global prevalence of yellow fever. One of the constant dangers for medical researchers studying infectious diseases is the risk of infection. Indeed, between 1928 and 1930, five scientists, including Noguchi, became infected with yellow fever and died. Theiler himself was infected in 1929 but survived and subsequently acquired immunity to the virus.

Using a combination of virus and immune sera, Wilbur Sawyer, the head of the Rockefeller Society laboratory, prepared the first yellow fever vaccine. Individuals injected with this mixture did not develop yellow fever and developed immunity to it. Although too costly for widespread use, the vaccine was used to immunize researchers. The virus strains cultivated by Theiler on mice gradually became the basis for the development of two vaccines. The first vaccine, derived from an attenuated mouse strain, was used by the French government in 1934 to protect residents in French West Africa, where the vaccine proved highly effective and convenient for administration, although not entirely safe (sometimes it caused encephalitis). Therefore, Theiler and his colleague developed a second strain. Designated as the 17D strain, it was obtained from the Asibi virus strain, which was grown on chick embryos with removed nervous tissue. Unlike the first strain, the new vaccine only caused mild reactions, if any; it was easier to mass-produce and became widely used in 1937. For many years, these two vaccines were highly effective in combating yellow fever, despite the later discovery that this disease occurs not only in humans. In Africa, in particular, it affects monkeys and periodically retransmits to humans through mosquito bites.

For his "discoveries concerning yellow fever and the methods of combating it," Theiler was awarded the Nobel Prize in Physiology or Medicine in 1951. At the award presentation, Hans Bergström from the Karolinska Institute noted that Theiler's discovery "gives new hope that we can cope with other viral diseases, many of which have a devastating effect and against which we are currently completely powerless." In addition to yellow fever, Theiler also studied other viral diseases. He had a particular interest in poliomyelitis and discovered a similar infection in mice known as mouse encephalomyelitis or Theiler's disease. In 1964, Theiler became a professor of epidemiology and microbiology at Yale University. He retired in 1967.

Personal Life and Achievements

In 1928, Theiler married Lillian Graham, and they had one daughter. In addition to his work, he enjoyed playing baseball and reading, particularly historical and philosophical books. While living in the United States, Theiler remained a citizen of South Africa.

Max Theiler passed away on August 11, 1972. In addition to the Nobel Prize, he received the Chalmers Medal from the Royal Society of Tropical Medicine and Hygiene (1939), the Flattery Medal from Harvard University (1945), and the Albert Lasker Award from the American Public Health Association (1949).