Smallpox was an infectious disease that caused fluid-filled blisters all over the body and had a mortality rate of 30-35%. Thanks to effective vaccination campaigns, smallpox became the first disease to be declared eradicated by the WHO on December 9, 1979. In this video, D.A. Henderson, an epidemiologist and physician who headed the eradication campaign, speaks about his efforts during that time. “It was a big problem and we knew we had to work in about fifty countries and we had around two and a half million dollars to do that.” The strategy he used has been used since to combat other infectious diseases: “To have some mechanism, a team, to go out, go to the place where the cases are, see if there are other cases around. You vaccinate them and you build kind of a wall around them of people, because smallpox will not exist in animals, it has to go from person to person to person.” Henderson also discusses bio-security, and being prepared in case of a bio-attack such as smallpox.