The last case was known in 1977 but no one was willing to raise any glasses, yet by early 1979 everyone knew the clocking was ticking. Finally, by the end of the year it was official. Smallpox was gone, and vaccines had done it. But not without help from those 150,000 pairs of boots on the ground and ... math.
Though from the mid-1960s until its eradication seems like a short time in an era where NASA can't even make a telescope without 14 years of overruns and delays, it had more challenges than science. Science not only had to fight the disease, Henderson had to fight World Health Organisation Director-General Marcolino Gomes Candau, who feared the optics if it failed and made it clear that his group was not taking the blame, it would be the United States and specifically Henderson, who the U.S. wanted to head the World Health Organization’s (WHO’s) Intensified Smallpox Eradication Programme.
A girl in Bangladesh with smallpox in 1973. By December of 1977 it had had been eradicated from the country. It involved vaccines, boots on the ground, and...math. Image via Wikipedia
That seems like an odd stance, since smallpox eradication was one of the few things that the USSR and USA worked together on during the Cold War, but the UN was already under fire for refusing to act as actual peacekeepers from Israel to Vietnam (1) and everywhere in between, their malaria program had not made progress (2), and they worried about more negative publicity, even if the upside was saving 15,000,000 smallpox cases a year in poor areas where 1.2 billion people lived. WHO even tried to starve the program after they caved into pressure from the USA and the Soviets, allocating just $2.7 million for it, less than what CDC alone had been doing with Henderson there.
(L) Dr. D.A. Henderson. (R) Dr. Bill Foege.
As it turned out, smallpox would be a big win for WHO, they list it at the top of their accomplishments. But they were resistant to it right to the end. They wouldn't even concede it was eradicated until 1980.
Dr. Henderson passed away in 2016 but Dr. Foege, who gets credit for the surveillance–containment strategy - the math involved in creating concentric rings to focus on based on how disease spreads - that was vital to pushing it farther and farther into the corner, is still with us. He became Chief of the CDC Smallpox Eradication Program and was appointed director of the CDC in 1977. That he is still with us does not mean he will check email but if you want to thank him, here is his address.
(1) They were under orders everywhere to just stand there without guns and let groups attack. The U.S., which did not trust Israel because of its socialism until that point, finally helped them specifically after yet another attack in 1968 where the U.N. prevented nothing.
(2) By then, they didn't want to use DDT because of Rachel Carson's activist book "Silent Spring", now they know better. And the U.S. banned DDT for political reasons but our EPA wrote the book on how to spray it inside homes in other countries.