Smallpox: Is it time to destroy the world's last few stockpiles?

The World Health Organization is expected to decide, this week, whether or not to destroy the world’s last remaining caches of live smallpox virus. So far, no verdict. Here’s what’s going on.

Smallpox, which killed more than 300 million people in the last century, was eradicated by 1980 through a worldwide vaccination campaign.

But, two stockpiles of the variola virus (pictured) still remain: one at the Centers for Disease Control and Prevention in Atlanta and the other in the Russian State Research Center of Virology and Biotechnology in Koltsovo (although a 135-year-old scabby bit was hanging out at a Virginia museum earlier this year).

Right after eradication was declared, WHO reached a consensus that existing lab stocks should be destroyed to eliminate the risk of accidental release. By 1984, stocks were either destroyed or transferred to those two repositories.

Many developing countries that would probably bear the brunt of any accidental release have long backed the destruction plan, but WHO has repeatedly pushed back the deadline under pressure from developed countries.

Health ministers from WHO’s 193 member states are still debating over this at the 64th World Health Assembly in Geneva, where the US will ask to delay destruction for another 5 years.

Many scientists argue that the stocks would help develop new countermeasures like drugs, vaccines, and diagnostics in case smallpox reappears.

“We’ve beaten smallpox once, but we must be ready and prepared to beat it again, if necessary,” writes Kathleen Sebelius, US secretary of health and human services. “Destruction of the last securely stored viruses is an irrevocable action that should occur only when the global community has eliminated the threat of smallpox once and for all.”

Many poorer countries, on the other hand, view smallpox research as a potentially dangerous luxury, and these officials are anxious to close the last chapter on the disease.

"You just can't provide 100% security," argues D.A. Henderson, head of the WHO's eradication campaign.

Developed countries also want to continue research that would protect against the consequences of a deliberate release by rogue states or terrorists, who may have access to undeclared stocks.

"If we knew for a fact when we would have these smallpox vaccines and antivirals fully developed and fully licensed, we would have no problem with a clear timetable for destruction,” says US delegate Nils Daulaire.

The WHO has emphasized that science alone cannot justify retention, and that any research must have tangible public health benefits.

The stocks, researchers say, would help explore the impact of smallpox on the immune system for insights into diseases such as AIDS. The past decade has seen progress in smallpox research, in particular the development of two new drugs (still unlicensed). Current vaccines are effective, but unsuitable for people with compromised immune systems, such as those with HIV.

Because clinical trials of new drugs and vaccines for the disease are impossible, US regulatory agencies currently demand that vaccines and drugs show efficacy in animals challenged with live smallpox. Unfortunately, a key problem for smallpox research is how there’s no good animal model for the disease.

"We're talking about getting the science right," Daulaire says. "We do favor the eventual destruction of the stocks once the primary goals of the research have been achieved. We don't think it's a never ending process." But, he adds: "Research has this nasty tendency not to be predictable. We don't know what the time horizon is."

Many scientists also argue that destroying the stocks would do little to protect the world from smallpox, since it’s possible to recreate the virus from its genome, which was sequenced in 1994.

WHO bio-safety inspectors visited the two repositories in 2009 and found them safe and secure for work with live virus, and the organization also maintains a vaccine emergency stockpile of 32.6 million doses stored securely in Switzerland.

Image: Fred Murphy / CDC

This post was originally published on Smartplanet.com