Smallpox Vaccine Testing Starts

Stash of 70 million doses could be stockpiled if found effective

MONDAY, July 8, 2002 (HealthDayNews) -- Laboratories from coast to coast are launching tests of a giant, hidden stash of smallpox vaccines, and they hope to have the results by next month.

"The goal is to potentially make 70 million doses available as a stockpile to vaccinate people nationally," says Dr. Steve Black, co-director of the Kaiser Permanente Vaccine Study Center, which began its test today.

If the doses can be successfully diluted, their numbers could multiply far enough to cover every man, woman and child in this country, Black says.

Aventis Pasteur announced in March that it would donate more than 70 million doses of smallpox vaccine to the government. The drug company has been keeping the vaccine on ice for decades.

According to a federal spokesman, the government considers the doses to be an "insurance policy" in case of an immediate bioterrorism attack. The government still plans to buy 209 million doses of new vaccine from other companies.

The government has hired four laboratories to test the Aventis Pasteur vaccines. The laboratories are at Vanderbilt University, Baylor University, the University of Iowa and the Kaiser Permanente Vaccine Study Center in Oakland, Calif.

About 350 people between 18 and 32 years old will be vaccinated during the testing, Black says. Officials chose that age range to ensure that none of those in the study had received the smallpox vaccine already.

"We want to make sure we're comparing apples to apples here," he says.

American health officials stopped routinely vaccinating people for smallpox in 1972. Millions of people born before that year still bear a small scar near their shoulders from inoculations, which are given using a multi-pronged device that repeatedly scratches the skin.

Half the population of this country has never been vaccinated against the virus. Experts say it's unclear if those who were immunized are still protected.

There are only two known supplies of the smallpox virus in the world, one held by the United States and the other by Russia. However, researchers don't need any smallpox virus to test the vaccine doses, Black explains.

Instead, researchers will check whether those who are vaccinated develop a blister at the sign of the inoculation. If the inoculation is successful, "over two- to three-week period, an infection will set up there and then heal with a scab and usually a small scar," Black says.

In the future, the person will be immune both to smallpox and the virus used in the inoculation.

Some people in the study will receive diluted doses to determine if those work as well as full doses, Black says.

It appears to be at least possible that one dose of smallpox vaccine could be divided into as many as 10 without much reduction in potency. In March, scientists at Saint Louis University announced that a study of 680 people found that diluted smallpox doses, all more than 20 years old, were almost always just as strong as full-strength viruses.

At Kaiser Permanente, even though the first subjects will get vaccinated today, the results of the tests aren't expected until August, Black says.

"It's on a fast track," he adds. "People want to know the answer to these questions sooner rather than later."

What To Do

For a history of the smallpox vaccine, check out Stanford University.

For more on bioterrorism and what officials are trying to do to stop it, try the National Memorial Institute for the Prevention of Terrorism or the Centers for Disease Control and Prevention.

SOURCES: Steve Black, M.D., co-director, Kaiser Permanente Vaccine Study Center, Oakland, Calif.
Consumer News