Fears about bioweapons have caused the United States to push the World Health Organization to open smallpox virus stores, which have been frozen since 1984 at the Centers for Disease Control in Atlanta.
In early November, an advisory committee recommended that researchers be allowed to work with variola, the virus that causes smallpox, to develop new preventions and treatments for the disease, a step that some view as necessary to repel a potential bioterrorist attack. However, the move could also increase the risk of accidental or surreptitious release of the virus.
For researchers, the tricky debate – which flared again after the September 11 terrorist attacks – has been going for years. Smallpox is an acute, extremely contagious disease that killed 300 million people in the 20th century alone. Symptoms are devastating: fever, blindness, and painful, pus-filled blisters that leave scars 30 percent of victims dont live to see.
Raymond Zilinskas, director of the Center for Nonproliferation Studies at the Monterey Institute of International Studies, said he is ambivalent about new studies. The threat is relatively remote, he said, so why increase the numbers of people handling variola, which increases the chance of a disaster? On the other hand, further study could prevent an outbreak or provide therapy if one occurred.
“On the balance, I believe that the oversight of future smallpox research will be adequate to prevent escape or purloinment of the virus,” said Zilinskas. “And the probability that this research will generate findings useful to medicine and public health is substantial, so let this research go forward.”
That’s an opinion that isn’t universally shared. When scientists finally eliminated the scourge of smallpox in 1980, many researchers thought the best next step would be to destroy the remaining samples of variola, and wipe the disease from the face of the earth.
“I would prefer that research with variola not be performed and that stocks of variola be destroyed,” said Richard Ebright, a professor of chemistry at the Waksman Institute of Microbiology at Rutgers.
The WHO decided in 1984, though, to keep two samples in the form of scabs and other cells from infected individuals: one in a Siberian lab called Vector and the other at the CDC in Atlanta.
Then, what many feared would happen, became a reality. While the CDC samples remained sealed, Russian scientists were busy re-engineering the virus during the cold war. Vats of super-virulent smallpox were then placed in missiles and pointed at the United States.
After the Soviet Union collapsed, the vats were reportedly destroyed.
Ken Alibek, a former bioweapons researcher in Russia, suggested in his 1999 book Biohazard that desperate-for-work scientists may have sold samples to rogue nations.
No one is thrilled about the prospect of poking at preserved smallpox scabs, but many believe that the present vaccine would not sufficiently protect Americans against an outbreak. They figure the risks inherent in opening up research are worth the potential benefit of discovering new vaccines or treatments
The only FDA-approved smallpox vaccine, Wyeth’s Dryvax, was developed by inoculating the virus into the scarified skin of live calves and scraping off the resulting pus, a frightening, old and dangerous technique.
The vaccine did prove to be effective, despite its occasional bacterial and viral contamination. For some, though, the cure would prove worse than the illness. Studies have found that the vaccine is harmful or even deadly to AIDS patients and pregnant women.
Making dire circumstances worse, as the amount of live virus diminishes over time, so does the vaccine’s effectiveness.
That prompted the U.S. government to make the case for opening the smallpox stores.
Experts say 40 million doses of vaccine are required to contain a U.S. outbreak, and the current stockpile contains only 15.4 million. But a study in 2002 found that the doses could be diluted to five times that number and still be effective, leading the CDC to declare on its website, “The United States currently has sufficient quantities of the vaccine to vaccinate every single person in the country in an emergency.”
But that’s little comfort for those who can’t safely use the vaccine. Even without access to the virus, scientists continue to press forward in their search for a better vaccine by using animal models of closely related “pox” viruses.
Acambis, a vaccine company in Cambridge, Massachusetts is developing a next generation vaccine that it hopes will be better tolerated by recipients. But the effort hit a speed bump in 2003 when research was halted because the vaccine caused heart problems in some people. But the FDA lifted its hold on the studies in September, and the company hopes to apply for approval soon.
Acambis previously had an exclusive contract with the U.S. government. But in July, President Bush signed a $5.6 billion bill, dubbed Project Bioshield, to encourage drug companies to develop vaccines – which are historically risky ventures – for smallpox as well as other potential bioweapons including Ebola, plague, botulism and anthrax.
Now a handful of other companies are pursuing treatments, including Chimerix in San Diego, Siga Technologies in Corvallis, Oregon, and Bavarian Nordic of Denmark.
Whether the FDA will accept their research remains to be seen. Traditionally, the agency requires that researchers show a drug is effective against the actual disease it’s purported to treat – another reason why health officials want to open up smallpox reserves.
If the United States gets its way, though, researchers may soon have direct access to the frozen samples, which may expedite the search for new vaccines.
One recommendation the WHO is considering would allow researchers to genetically engineer variola to make it glow. Eerie as it sounds, inserting a green fluorescent protein into organisms to follow genetic expression is a basic and common procedure. Another recommendation would permit the CDC smallpox repository labs to insert single variola genes into orthopox viruses in animals such as monkeys and cows.
Two other recommendations would allow the Russian and American teams to share their smallpox samples for the first time, so researchers could work on projects simultaneously.
“It isn’t really a huge risk,” said Dave Evans, a member of the WHO smallpox advisory committee and University of Alberta professor of microbiology and immunology. “The CDC laboratories are very well contained, so the experiments themselves can be done in a very straightforward manner, as long as you follow containment rules and assure the staff is properly vaccinated.”
The World Health Assembly will decide whether to accept the recommendations, allowing the CDC freezers to be cracked open, in May 2005.