Donald Ainslie “D. A.” Henderson (September 7, 1928 – August 19, 2016) was an American physician, educator, and epidemiologist who directed a 10-year international effort (1967–1977) that eradicated smallpox throughout the world and launched international childhood vaccination programs. From 1977 to 1990, he was Dean of the Johns Hopkins School of Public Health. Later, he played a leading role in instigating national programs for public health preparedness and response following biological attacks and national disasters. At the time of his death, he was Professor and Dean Emeritus of the Johns Hopkins Bloomberg School of Public Health, and Professor of Medicine and Public Health at the University of Pittsburgh, as well as Distinguished Scholar at the UPMC Center for Health Security.

Born: Donald Ainslie Henderson (September 7, 1928 – Lakewood, Ohio)
Died: August 19, 2016 (aged 87) – Baltimore, Maryland
Nationality: American
Fields: Epidemiology
Institutions: World Health Organization, Johns Hopkins University
Known for: Eradicating smallpox
Notable awards: Ernst Jung Prize (1976), Public Welfare Medal (1978), National Medal of Science (1986), Japan Prize (1988), Albert B. Sabin Gold Medal (1994), Presidential Medal of Freedom (2002)