retreated from Europe, the Soviet Union, and North America. It remained a scourge of tropical
countries with poor medical systems in place. But it was beaten so far back that some public health
workers began to contemplate an audacious goal: eliminating smallpox from the planet altogether.
The advocates of smallpox eradication built their case on the biology of the virus. Smallpox only
infects humans, not animals. If it could be systematically eliminated from every human population,
there would be no need to worry that it was lurking in pigs or ducks, waiting to reinfect us. What’s
more, smallpox is an obvious disease. Unlike a virus like HIV, which can take years to make itself
known, smallpox declares its gruesome presence in a matter of days. Public health workers would be
able to identify outbreaks and track them with great precision.
Yet the idea of eradicating smallpox met with intense skepticism. If everything went exactly
according to plan, an eradication project would require years of labor by thousands of trained
workers, spread across much of the world, toiling in many remote, dangerous place. Public health
workers had already tried to eradicate other diseases, like malaria, and failed.
The skeptics lost the debate, however, and in 1965, the World Health Organization launched the
Intensified Smallpox Eradication Programme. The eradication effort was different in many ways from
previous campaigns. It relied on a new prong-shaped needle that could deliver smallpox vaccine far
more efficiently than regular syringes. As a result, vaccine supplies could be stretched much further
than before. Public health workers also designed smart new strategies for administering vaccines.
Trying to vaccinate entire countries was beyond the reach of the eradication project. Instead, public
health workers identified outbreaks and took quick action to snuff them out. They quarantined victims
and then vaccinated people in the surrounding villages and towns. The smallpox would spread like a
forest fire, but soon it would hit the firebreak of vaccination and die out.
Outbreak by outbreak, the virus was beaten back, until the last case was recorded in Ethiopia in- The world was now free of smallpox.
While the eradication campaign was a huge success, the smallpox virus had not disappeared
completely. Scientists had established stocks of the virus in their laboratories to study. The WHO had
all the stocks gathered up and deposited in two approved laboratories, one in the Siberian city of
Novosibirsk in the Soviet Union, and one at the U.S. Centers for Disease Control and Prevention in
Atlanta, Georgia. Smallpox experts could still study stocks from the two labs, but only under tight
regulations. Most experts assumed that before long those last two collections of smallpox would be
destroyed as well, and then the virus would become truly extinct.
It turns out, however, that there might actually be more smallpox virus in the world. In the 1990s,
Soviet defectors revealed that their government had actually set up labs to produce a weaponized
smallpox virus that could be loaded onto missiles and launched at enemy targets. After the fall of the
Soviet government, the labs were abandoned. No one knows what ultimately happened to all the
stocks of smallpox virus. We are left with the terrifying possibility that ex-Soviet virologists sold
smallpox stocks to other governments or even terrorist organizations.
When these revelations emerged, some scientists and government officials decided the research
stocks had to be preserved. Scientists could study them to help prepare for biological warfare. There