Of course, it's a little harder to be clear when the war on smallpox was really won. The last patient was diagnosed in 1977 (he survived), and it's by no means certain that the last wild specimens of the virus were in him; possibly some unidentified infected person was hit by a bus in 1978 or even 1987 and took the last ones with her. We only know we won because enough time went by without any new infections to give us some confidence that it's over. There were no parades or fireworks.
But even so, it was a truly stunning accomplishment. I mean, we've driven countless species extinct before, but mostly unintentionally and to our detriment. Smallpox was a vicious virus whose only role in the ecosystem, so far as anybody can tell, was to hitch a ride from human to human, killing lots of us in the process. The defeat of smallpox was one of the best things that has ever happened for our species.
And defeating it took enormous organization, resourcefulness, skill and courage. The last person to be infected? He was a hospital cook who worked with the WHO team working to eradicate smallpox. And the last person to die of smallpox was a medical photographer. So fighting diseases is not without its risks.
Yet it wasn't only the medical professionals going out and vaccinating people who won this war. There wasn't always enough vaccine to go around, and so it had to be applied strategically. That meant getting good intelligence on where the virus was. New cases anywhere in the world were reported quickly to the team, who would isolate the patient and vaccinate all her contacts. The last natural infection of the deadliest strain (the hospital cook got a somewhat less deadly but still dangerous version) was reported to the authorities by an 8 year old girl, so there were important contributions made by everyone. And that includes everyone who received a vaccination (which can be a scary thing, especially for children).
So we should all be grateful and celebrate this anniversary, but not just because ending smallpox was a good thing. Deadly infectious diseases like smallpox are kind of like war in that most of us, living in the developed world, haven't directly experienced one, and can scarcely imagine the epidemics of even the recent past. Influenza killed more people in the years of the Armistice and the Treaty of Versaille than the four years of war they ended. Lest we forget.
We should remember these things so we don't repeat them. When we debate whether or not to get vaccinated against the diseases we're still fighting, we should remember what we're up against, and bravely, proudly, patriotically roll up our sleeve and take that shot. Even if you believe that vaccines can cause autism (they really don't), even if you're afraid of all the (very rare) complications from vaccines, remember that you live free of smallpox because of people who were willing to be vaccinated despite their fear of these strange foreign doctors and their needles. And generations yet unborn may have reason to be grateful to us for a life free of polio, measles, the Guinea worm and other pestilences we might yet defeat.