The world's last known samples of smallpox seemed destined for destruction. Then came Sept. 11

By Michael Purdy
Art by Tom Curry

The tone of the two-decades-long debate over whether or not to destroy the last known samples of the smallpox virus shifted dramatically after Sept. 11 and the fall anthrax attacks.

In mid-November, the Bush administration formally announced that it intended to indefinitely postpone the planned 2002 destruction of U.S. smallpox stocks. Then on Jan. 17, the executive board of the World Health Organization recommended extending the deadline for destroying the smallpox samples kept in high-security labs in the United States and Russia. The board cited the potential use of the stocks in the development of antiviral drugs.

For the moment, the argument seems to have tilted to favor the preservationists; however, those seeking destruction of the smallpox stocks — including Dean Alfred Sommer — battle on.

Before it was brought under control through an aggressive, international vaccination program in the 1960s and 1970s, smallpox cut a centuries-long path of misery and death across the globe. The highly contagious disease, for which no successful treatment beyond vaccination has ever been developed, causes a rash that can disfigure or blind sufferers, and kills about one in every three people it infects.

D.A. Henderson, the scientist who led the worldwide effort to eliminate smallpox in the wild, had been a formidable advocate for destruction as the leader of the School's Center for Civilian Biodefense Strategies. He says the attacks of last fall have not changed his views, but he has stepped out of the debate since becoming the director of the federal Office of Public Health Preparedness.

"I'm now a member of the government and it is a government position that we should retain the smallpox virus," Henderson says. "What more can I say?"

Once in favor of destroying the smallpox stocks, Frank Calia, MD, vice dean of the University of Maryland School of Medicine, says his mind was changed by the events of last fall. Calia, an infectious disease specialist who's not involved in smallpox research, calls the elimination of smallpox in the wild "so wonderful it boggles the mind." But he says he is deeply concerned by reports that there may be additional stockpiles of smallpox in the hands of terrorist groups or rogue states like Iraq or North Korea.

"Had there been only two stockpiles of the virus, and they were both destroyed and we were sure of that, that would've been the best eventuality for humanity," Calia says. "However, we don't know that those are the only two repositories of the virus."

Calia also worries that smallpox immunizations have not been given for decades, leaving most of the population vulnerable to a potential outbreak.

"I'm sympathetic to the desire to destroy smallpox, but under the current situation, the current threat, we need to know more things about it," Calia says. He feels that the more scientists can learn about smallpox, the better prepared the world will be to deal with a renewed outbreak if smallpox is unleashed again.

"So much has been learned since smallpox was eliminated as a problem in the 1970s," says Calia, pointing out the many advances in viral research and treatment since the emergence of the HIV epidemic in the 1980s. Calia would like to see some of those advances, including new antiviral drugs and potential new smallpox vaccines, tested against smallpox in an in vivo model of the disease, and he thinks a primate model of smallpox announced by U.S. Army researchers at Fort Detrick, Maryland, in January may be able to meet that need.

However, Sommer disagrees. He strongly criticized the monkey model in a Baltimore Sun op-ed and in news stories. Sommer, who fought a staggering outbreak of the disease in Bangladesh in 1972, decries the example that the primate research sets for other countries. "Playing with this virus, and keeping it alive and showing other countries that we are experimenting with it in primates - are they really going to believe that we're doing this only for defensive purposes?" Sommer asks. "No. Everybody's going to go out and want to get their virus for ostensibly 'defensive' purposes as well."

Sommer, MD, MHS '73, emphasizes that the smallpox virus is not needed for the development of new vaccines. Smallpox is caused by a virus known as variola, but the smallpox vaccine is actually made from a related but less virulent virus, vaccinia, that infects humans and cows.

To the human immune system, vaccinia looks a great deal like variola. Immune cells can easily wipe out the milder vaccinia, and in the process become primed to exterminate its tougher cousin variola.

Sommer adds that the existing smallpox vaccine, "which did, after all, eradicate the disease," is perhaps one of the biggest reasons he feels the debate should be swinging toward destruction. "In the last couple of months, we have taken smallpox seriously, which means that we will soon have enough doses [of the vaccine] for everybody in the United States, and we will have a plan that will allow us to rapidly distribute and administer vaccine in the U.S. to everyone for whom it is safe to administer," Sommer explains.

Although a weakened virus, vaccinia is a "live" vaccine, which makes it highly effective at simulating an infection and provoking an immune system response in healthy persons. People with weakened immune systems, however, may be unable to prevent it from causing a potentially life-threatening infection. The Bush administration wants a vaccine safe for immunocompromised individuals before destroying smallpox.

Sommer suggests that instead, researchers should be working on ways to help them survive vaccinia, the disease they might get from the smallpox vaccine. Or that public health officials develop "reverse-quarantine" protocols so that those with weakened immune systems would not receive the vaccine and would limit personal contacts during an outbreak to those who have already been vaccinated.

In the ability to destroy the last remnants of smallpox, Sommer sees a chance almost never given to science. "This is one of the most dreaded diseases that mankind has ever faced. It has killed hundreds of millions of people. And here we have an opportunity to make it disappear forever as a cause of disease," Sommer says.

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