CDC's stock of smallpox-causing virus source of debate

“If the U.S. maintains its current position on indefinite retention of the live virus, I can foresee a diplomatic train wreck at the World Health Assembly in May,” said Jonathan B. Tucker, author of "Scourge: The Once and Future Threat of Smallpox."

Dr. Inger Damon, chief of the Poxvirus and Rabies branch with the CDC, says the debate entails more than just science: "I think there is probably quite a bit of geopolitical posturing on this," she said.

In addition to a high fever, smallpox causes the sufferer's body to slowly erupt with painful blisters that some describe as feeling like BB pellets under the skin. About a third of people with smallpox die. Survivors are often left disfigured and blind.

The disease is both one of mankind's greatest scourges and most brilliant triumphs. An intensive worldwide vaccination campaign launched in 1967 eradicated smallpox, with the last known case reported in Somalia in 1977. (The last U.S. case was in 1949.) However, there still is no cure.

While most countries voluntarily destroyed or handed over their variola virus reserves in the late 1970s, the U.S. and Russia have for decades repeatedly pushed to hold onto their stocks, citing the need for further research.

After all, no one knows for sure whether the U.S. and Russia are the sole proprietors of the deadly virus.

"[Handing over the virus] was a voluntary effort," Damon said. "There was no extensive checking of freezers and checking of vials."

In a statement issued by the U.S. Department of Health and Human Services, government officials maintained the need for keeping the reserves. The statement pointed to a scientific review of the variola virus research conducted from 1999 to 2010, which concluded additional research was necessary.

"More work has to be done on the vaccine," said CDC spokesman David Daigle. "We want to make a better vaccine without side effects and we have much more work to be done [with developing] antivirals."

Though the U.S. has a stockpile of roughly 350 million doses of vaccine should an outbreak occur, the current vaccine cannot be taken by everyone. People whose immune systems are compromised, for example, cannot take the vaccine, he said.

Fewer than 10 people have access to the American-held variola virus reserves, more than 450 vials frozen in liquid nitrogen. The virus is guarded by greater security measures than such biological agents as anthrax,  said Damon, one of those with access to the stock. Indeed, smallpox is as tightly contained as the Ebola and Marburg viruses.

While many scientists such as Damon believe the virus should be retained for research, others fear the risk of keeping the live virus is greater than destroying it.

Tucker urged the U.S. government in a recent article to compromise with the international community, either by setting a date for destruction of the virus stocks held in the U.S. and Russia, or by reducing the number of samples to a fraction of the current number and sharing any drugs or vaccines that result from the research with all WHO member states.

“At some point, the U.S. has to show more flexibility," he said.

Tucker and others argue that the U.S. now has an adequate set of medical defenses against smallpox, including enough vaccine to protect its entire population. He also questions whether the U.S. can achieve its goal of developing a realistic model of smallpox in monkeys with which to test new antiviral drugs against the disease.

While that effort proceeds, Tucker is concerned about the possibility of a scientist becoming infected accidentally or perhaps even releasing the virus deliberately, a scenario he considers unlikely but still possible.

He also rejects the notion that the U.S. should retain stocks of the live virus because other countries might have secret stores that they could use for biological warfare.

“The logic of deterrence doesn’t hold in this area,” he said. “If we were attacked with smallpox, we wouldn’t retaliate with smallpox. That would be morally repugnant."

Dr. Jeffrey Koplan, director of the Emory Global Health Institute and former director of the CDC, said he doubts that the U.S. would be willing to destroy its reserves, even if the WHA votes in May to set a destruction timeline.

"The overriding factor is that politically it would be difficult for any administration to order the destruction of the virus while the Soviet Union still kept it in their fridge," he said.

One thing that is sure to survive? The debate -- just as long as the virus does.

“It will not go away," Koplan said.