The revival of smallpox inoculations in the United States brings back a vaccine considered the most dangerous of all. President Bush's decision to order its use in certain cases balances preparedness with caution.
There is irony in the fact that the first disease to be eradicated from Earth is back to haunt policymakers, who fear that an act of bioterrorism could expose U.S. citizens once again to the deadly virus.
A global vaccination campaign stamped out smallpox in the 1970s, leaving the only official stores of it locked up in U.S. and Russian government research facilities. But U.S. officials do not discount the possibility that some samples may have been stolen or never destroyed in the first place. Could they get into the hands of bioterrorists? Could Iraq release it as a defense against a U.S.-led attack?
President Bush's decision to order the vaccination of half a million military personnel and recommend it for an equal number of health workers shows that he considers these possibilities real. But by making vaccination voluntary among the rest of the U.S. population, he acknowledges the problems with the smallpox vaccine and agrees with last year's World Health Organization warning not to require inoculation of entire populations.
"I think it's something the president has struggled with because it is such a dangerous vaccine," said Dr. Sue Bailey, a former Assistant Secretary of Defense for Health Affairs who spoke about the smallpox vaccine's dangers on NBC television's Today program. "I think we have to be sure to inform them of that fact, that this isn't modern medicine, that this isn't a vaccine that's produced by the best of technology," she said. "It's an old, dangerous vaccine and so I think people really need to be informed so they can make a good decision."
While other vaccines incorporate a killed or weakened virus to train a person's immune system to be ready for an attack, the smallpox vaccine is toxic because it uses the live vaccinia virus. Studies of its use in the 1960s showed that between 15 and 50 people of every million inoculated suffer life-threatening side effects such as the brain inflammation encephalitis and the skin inflammation eczema. One or two of them die.
Furthermore, the former U.S. public health official who led the smallpox eradication effort, Donald Henderson of the Johns Hopkins University Center for Civilian Biodefense Studies, said vaccination even threatens many who do not get inoculated. "Not only is this vaccine more reactogenic, causing more serious reactions than any other vaccine we have, but it is not just the individual who receives the vaccine who is at risk," he said. "So you have the potential of transferring vaccine virus to others. Indeed, in the surveys done in 1963 and '68, there were as many cases among those who were contacts as there were individuals who had received the vaccine."
As a result of the risks of smallpox vaccine, Dr. Sue Bailey said a large segment of the U.S. population should not get it, even if there is a smallpox outbreak. "How many people in this country today should not be vaccinated because they have weakened immune systems, because they are on cancer medications or they are HIV-positive or they have had a transplant or even people with a skin disease like eczema," she said. "And also infants and pregnant women. So you can see that's about 50 million Americans that should not be vaccinated and, in fact, should not be around someone who has been vaccinated."
There is hope, however, that the current smallpox vaccine will be needed only temporarily while scientists develop a safer version. That is the goal of the U.S. government's National Institute of Allergy and Infectious Diseases, whose director is Dr. Anthony Fauci. "We're going second generation and third generation vaccines, but a vaccine candidate that has very little toxicity - namely a modified form of vaccinia which we feel can be safely given to people who are immunosuppressed [have weakened immune systems]. That's obviously more than a year and probably a couple of years away, but that's the ultimate goal," he said.
Dr. Henderson said that regarding the present smallpox vaccine, he hopes the Bush administration will evaluate the results of its early inoculations before offering them to the public.