Analysis: U.S. vulnerable to smallpox's return.

2003 JAN 8 - (NewsRx.com & NewsRx.net) -- It was one of history's greatest triumphs: eliminating a disease that killed hundreds of millions of people and was feared across the globe.

Yet in a new world of terrorist threats, smallpox is feared again, and the Bush administration is set to offer a vaccine that will kill and seriously injure at least some in order to fight a battle public health thought it had won.

"I must confess, I thought we'd seen the very last of smallpox vaccine," said Dr. D.A. Henderson, who led the global campaign that wiped out smallpox. "It troubles me every time I think about this."

In a stroke of historic irony, it's the triumph over smallpox that makes the world so vulnerable to it now. As the disease was on the wane, vaccinations ended, leaving the entire population unprotected. Experts believe that people vaccinated more than 30 years ago have little if any protection today against the highly contagious, often-deadly disease.

In the decades since, thinking about smallpox has undergone a remarkable transformation.

Bioterrorism experts now paint frightening scenarios like this one: smallpox distributed covertly through a hotel's air ventilation system. Or this one: suicide smallpox patients infect themselves with the virus and, when they are at their most contagious, stumble through airports, infecting hundreds of others who then carry the virus across the country and possibly around the world.

Thoughts like that were never mentioned back in 1977, when the last naturally occurring case of smallpox occurred, or in 1980, when the disease was declared eradicated. All stocks of smallpox - except for samples kept by special labs in Moscow and Atlanta - were supposed to be destroyed, and for more than a decade, smallpox was considered a thing of the past.