Acambis, which had already promised to deliver 54 million doses of the shot, will team up with Baxter International, of Deerfield, Ill., to make the vaccine in Europe and ship it to the Centers for Disease Control and Prevention within the coming year. Health and Human Services Secretary Tommy Thompson announced the contract yesterday.
The expanded production took on particular urgency in the wake of the Sept. 11 terrorist hijackings and the subsequent anthrax attacks that have so far killed five people."While the probability of an intentional release of the smallpox virus is low, the risk does exist and we must be prepared," Thompson says in a statement. "Expanding our stockpile so there is a smallpox vaccine for every American if needed prepares us to respond aggressively to minimize the spread of the disease should an outbreak occur. Additionally, we hope that increasing our smallpox vaccine stockpile would serve as a deterrent to those who might consider using smallpox as a weapon against us."
Routine vaccination against smallpox ended in the United States in 1972, and the World Health Organization declared the naturally occurring virus eradicated in 1980. But the pathogen has been kept alive in government labs both in this country and Russia, and possibly in Iraq and North Korea, and terrorism experts have long feared the devastation that would follow the release of the organism on an unvaccinated population. Since the vaccine's effectiveness may wane after 15 to 20 years, even immunized individuals may be at risk.
Although the government says it has no plans for mass inoculations, the contract with Baxter and Acambis, plus the stock of other vaccine already available or in development, is enough to cover as many as 286 million Americans. The U.S. Census estimates the population at about 285.6 million.
Thompson says the two companies agreed to provide the vaccine at a fixed price of $2.76 per dose. Any cost overruns will be borne by the manufacturers, officials say.
The vaccine relies on live, purified vaccinia virus, a relative of smallpox, to stimulate an antibody response that fights off infection with the deadly microbe, which has been known to kill as many as 30 percent of the people who contract it. It has not yet been tested in humans, nor has the Food and Drug Administration approved the shot.
Gordon Cameron, president and chief financial officer of Acambis, says the company has "a bunch of pre-clinical data that gives us a lot of confidence" that the product, which is based on the earlier smallpox vaccine, is safe and effective.
The government has 15.4 million doses of the old "Dryvax" vaccine, kept as a precaution after production stopped in 1983. Researchers are now testing whether those doses can be safely diluted to cover as many as 77 million people. Initial results have been promising, officials say, and everyone who has received the one-to-five dilution has generated an immune response to the injection.
Earlier this week, the CDC released its plan for dealing with a smallpox outbreak. That strategy focuses on containing infections through "ring vaccination" and quarantines, but not on widespread immunizations.
Dr. William Schaffner, a smallpox expert at Vanderbilt University in Nashville, Tenn., says any strategy to inoculate large numbers of people is going to run up against several important hurdles. The first, he says, is that the vaccine is an old concoction. While it's powerfully active in the immune system, it also carries significant side effects at rates higher than more modern vaccines for other diseases.
"If we want a vaccine now, we're out buying a perfectly good 1958 Mercury, we're not buying a 2001 Toyota," Schaffner says.
Another obstacle, he says, is that smallpox vaccine isn't easy to administer. It requires a two-pronged needle that demands special training to use -- training most of today's health care workers don't have.
Finally, says Schaffner, there many more people in the modern population with weakened immune systems who might respond poorly to the smallpox vaccine than there were 30 or 40 years ago. The nation is older, and the elderly have less robust defenses against infection; there are more transplant recipients and other patients using steroids that suppress their immune systems; and there are people with HIV, which saps immune health.
"We're going to have to figure out what to do with them because it's a live virus that we're dealing with" in the inoculation, Schaffner says.
In an unrelated move, officials at the Nuclear Regulatory Commission say they've set aside $800,000 to provide states with "millions" of doses of potassium iodide in the event of a nuclear accident. The chemical jams the thyroid gland with normal iodine and locks out radioactive forms of the element. It was used to protect some people exposed to heavy radiation after the 1986 Chernobyl nuclear disaster in the Ukraine.
William Beecher, a spokesman for the NRC, says the agency is waiting for guidance from the FDA on when to make the drug and at what dose. Once the deal goes through, states will buy the doses and distribute them as they choose. "It will be a supplement to evacuation or sheltering in the event of an accident," he says.
Beecher stresses that potassium iodide is not "the Cipro against radiation." Rather, the drug is only useful for one thing: preventing thyroid cancer in the event of radiation exposure. "But that's not insignificant," he adds.
Beecher says the purchase plan "has nothing to do with Sept. 11th. This was in progress long before that, but obviously we're getting increasing interest."
What To Do
For more on bioterrorism and what officials are trying to do to stop it, try the Oklahoma City National Memorial Institute for the Prevention of Terrorism or the Centers for Disease Control and Prevention.
For a history of the smallpox vaccine, check out Stanford University.