Smallpox could come back it's being held in labs all it would take is a accidental or purposeful release, just like how the world was exposed to covid-19.
"I feel that someday we are quite likely to see smallpox again. Because it's held in human hands. And human hands are weak. And the human heart has dark corners to it," says Richard Preston.
He's written a book called "The Demon in the Freezer," about how the smallpox virus has been turned into a weapon of mass-destruction.
"Smallpox as a weapon is the biological equivalent of the nuclear bomb. It is simply the most dangerous biological weapon in the world,"
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