Wilbur Augustus Sawyer was born on August 7, 1879, in Appleton, Wisconsin, the eldest of Wesley and Minnie Sawyer's four children. Wesley Sawyer taught literature, political science, and German at the state teachers' college until 1885, when the family moved to Dresden, Germany, so that Mr. Sawyer could work on a German grammar text. When they moved back to the United States in 1887 Wilbur and his younger brother John, who had attended German schools, could no longer speak English. The family relocated to San Jose, California, where Mr. Sawyer took a post at the University of the Pacific. Wilbur attended the Belmont School in Belmont, California (where his father taught French and German), and started college at the University of California, Berkeley. He transferred to Harvard University in his second year, and got his AB there in 1902. He attended Harvard Medical School, received his MD in 1906, and then completed a two-year medical residency at Massachusetts General Hospital. Sawyer's diaries from this period also record his participation in school debates and Harvard's German Club, frequent visits and outings with various friends and relatives in the Boston area, and vacation trips to the New England shore.

In 1908, Sawyer returned to California to take a position as Medical Examiner in the University of California's infirmary, where he examined incoming freshmen and cared for university students and staff. He also taught in the Department of Hygiene and filled in at the State Hygienic Laboratory, then located on the UC campus. In 1910, he was appointed director of the Hygienic Laboratory. He married Margaret Henderson, a bacteriologist who taught at UC, in 1911, and they had four children. In 1915 he became secretary and executive officer of the California State Board of Health, and moved his family to Sacramento.

During his years at the State Hygienic Laboratory Sawyer earned a solid reputation as a public health administrator in California. He and his staff tracked down and treated cases of rabies, traced outbreaks of typhoid carried by sailors, and forged strategies for controlling venereal diseases and other common public health problems. Several years as a state board of health officer increased his administrative experience and expanded his involvement in national public health organizations and interstate and national health policymaking. After the U.S. started mobilizing for World War I in 1917, Sawyer, like many physicians, joined the Medical Reserve Corps. From 1918 to early 1919 he was charged with coordinating vice-control programs (focusing on venereal diseases) at the embarkation port of Newport News, Virginia. During this period he also served as assistant secretary to the American Social Hygiene Association.

In the course of his wartime duties, Sawyer became acquainted with a number of Rockefeller Foundation (RF) officers, and discussed working on various public health projects after the war. In June 1919 he went to work for the RF International Health Division; his first assignment was to set up hookworm control projects in Australia. For the next five years he directed the hookworm campaign there, and served as assistant director for the East, helping Dr. Victor Heiser supervise projects in Ceylon, Siam, and Indonesia. He also served as an advisor to the newly established Australian Ministry of Health.

After returning to the U.S. in 1924, Sawyer was appointed director of the Rockefeller Foundation's public health laboratory service. There his responsibilities included establishing cooperative relationships with state and local health departments, especially in areas where the RF operated hookworm and malaria-control projects.

In late 1926, Sawyer was sent to Lagos, Nigeria, as acting director of the RF West Africa Yellow Fever Commission, and joined the small group of investigators researching the disease there. In between administrative duties, he helped test a variety of potential lab animals for susceptibility to the disease, and investigated reported cases among the local population. Though Sawyer left shortly before several breakthrough discoveries were made, he was a primary investigator in subsequent research. In 1928, the RF established a small yellow fever laboratory at the Rockefeller Institute, and appointed Sawyer its director.

At the Yellow Fever Laboratory, Sawyer and his colleagues built on the important work that had been done by the West Africa Yellow Fever Commission. They developed techniques to preserve the virus for long periods, compared virus samples from Brazil and West Africa and proved them to be the same organism, and in 1931 developed and refined the first effective yellow fever vaccine. Sawyer also helped to develop a test for yellow fever immunity using mice (the mouse protection test) and used this to carry out an international survey of yellow fever exposure and to map where the disease had occurred in recent generations. In 1937, Dr. Max Theiler, working at the Yellow Fever Laboratory, developed a safer attenuated yellow fever virus, the 17D strain, and methods for producing the vaccine in large quantities, thus making mass vaccination programs feasible.

Sawyer became director of the RF International Health Division (IHD) in 1935, and continued to oversee the Yellow Fever Laboratory when his other duties permitted. As director he traveled extensively all over the world. During World War II, he and other leading public health administrators--civilian and military--worked together to assess the public health effects of the war and to plan relief efforts. As head of the IHD, Sawyer also organized and directed the RF Health Commission in its efforts to control typhus and malaria in the Mediterranean.

The war also created a huge demand for yellow fever vaccine. The Rockefeller Foundation agreed to manufacture as much as the American forces required, as a contribution to the war effort. Early in 1942, some American troops developed infectious hepatitis from the human blood serum used to make the vaccine. Sawyer accepted responsibility, as he had made the decision to stay with a serum-based vaccine, rather than use a newer non-serum method. Production was quickly changed, but the episode was embarrassing for him and for the RF.

In 1944, Sawyer retired from the Rockefeller Foundation, and became Director of Health for the United Nations Relief and Rehabilitation Administration (UNRRA), established the previous year to help provide food, shelter, and clothing, and to restore agriculture, industry, and public health services to civilians as the Axis forces retreated. In 1946 he participated in planning meetings for the World Health Organization (WHO). By 1947, that organization had been set up, and with the initial post-war work finished, UNRRA was dissolved. Sawyer and his wife moved back to Berkeley, California in 1949. He died there of congestive heart failure on November 12, 1951.

Sawyer published steadily throughout his career, including two dozen articles on yellow fever. He was a fellow of the American Public Health Association, the American Association for the Advancement of Science, and the Royal Society of Tropical Medicine and Hygiene. He served as president of the American Society of Tropical Medicine (1943-44) and participated actively in many other professional organizations even in retirement. He was an enthusiastic photographer most of his life, and an avid amateur botanist, an interest he shared with his wife, Margaret.

Sawyer received many recognitions and awards, including the first Leon Bernard Prize in International Public Health (1939), the Richard P. Strong Award from the American Foundation for Tropical Medicine (1949), and an honorary LL.D. from the University of California (1945). Many colleagues, especially at the Rockefeller Foundation, believed that Sawyer should have shared the 1951 Nobel Prize in medicine or physiology with Max Theiler, for his contributions to the yellow fever vaccine.