A Pox

Smallpox was one of the most devastating diseases humanity has ever faced, killing more than 300 million people in the 20th century alone.

 But thanks to the most successful global vaccination campaign in history, the disease was completely eradicated by 1980.

 By surrounding the last places on earth where smallpox was still occurring -- small villages in Asia and Africa -- and inoculating everyone in a wide circle around them, D. A. Henderson and the World Health Organization were able to starve the virus of hosts. 

Smallpox is highly contagious, but it is not spread by insects or animals. 

When it is gone from the human population, it is gone for good. 

But Errol Moris writes in the NYT that Henderson didn't really eliminate smallpox. 

 In a handful of laboratories around the world, there are still stocks of smallpox, tucked away in one freezer or another. In 2014 the CDC announced that vials containing the deadly virus had been discovered in a cardboard box in a refrigerator located on the National Institutes of Health (NIH) campus in Bethesda, Maryland. 

How can you say it's eliminated when it's still out there, somewhere?

 The demon in the freezer.

Some scientists say that these residual stocks of smallpox should not be destroyed because some ruthless super-criminal or rogue government might be working on a new smallpox, even more virulent than existing strains of the virus.

 We may need existing stocks to produce new vaccines to counteract the new viruses. 

Meanwhile, opponents of retention argue that there's neither need nor practical reason for keeping the virus around.

 In a letter to Science Magazine published in 1994, the Nobel laureate David Baltimore wrote, "I doubt that we so desperately need to study smallpox that it would be worth the risk inherent in the experimentation." 

 It all comes down to the question of how best to protect ourselves against ourselves.

 Is the greater threat to humanity our propensity for error and stupidity, or for dastardly ingenuity?

 http://www.themiddleages.net/plague.html