A doctor, Henderson, who preferred to be known as “D.A.” (for Donald Ainslie), was an epidemiologist. In 1955, he joined the Centers for Disease Control and Prevention’s Epidemic Intelligence Service. In 1960, he was promoted to Chief of the CDC virus disease surveillance programs. There, he came up with a plan to eradicate smallpox, one of the most virulent human viruses. In the 20th century alone, smallpox was estimated to have killed 300 million people — perhaps billions over human history; it evolved from a different virus over 10,000 years ago. Smallpox was so terrible that it was the first disease doctors tried to prevent with a vaccine: In 1796, British doctor Edward Jenner discovered that immunity to smallpox could be created by inoculating a person with goo from a cowpox lesion; cowpox was a milder disease, less likely to kill. The word “vaccine” is based on the Latin word vacca — cow — from that effort. Henderson got the go-ahead — and funding — to start his eradication effort in 1966, and was assigned to the World Health Organization to implement it.
“The sense at the W.H.O. was that this was an impossible mission, so they chose a young man who didn’t have a reputation to tarnish,” said Dr. Thomas V. Inglesby, director of the UPMC Center for Health Security in Baltimore. “I don’t want to say as cannon fodder, but something like that.” Henderson had a different take: “D.A. always said they wanted an American to blame,” said Dr. William H. Foege, who worked on the project with Henderson. Yet it took only 10 years to accomplish the eradication: the last known case of smallpox was in Somalia, in 1977. Dr. Henderson and his team is thus responsible for saving tens of millions of lives, perhaps hundreds of millions over time. Henderson was awarded the Presidential Medal of Freedom in 2002, the National Medal of Science, the National Academy of Sciences’ Public Welfare Medal, and scores of other recognitions. He became the dean of the Johns Hopkins Bloomberg School of Public Health (1970-1990), and finished his career at UPMC. He never retired, preferring to work on other problems, including antibiotic-resistant infections, such as staph. Dr. Henderson broke his hip, acquired an antibiotic-resistant staph infection, and died on August 19. He was 87.