Panel: No Mass Smallpox Vaccinations Needed

CDC experts say some health-care workers should be inoculated

THURSDAY, June 20, 2002 (HealthDayNews) -- Despite the dark shadow of bioterrorism and government warnings about the risk of new attacks with deadly pathogens, a group of vaccine experts said today that a return to mass immunization against smallpox isn't necessary.

But the group, the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices, said that advice might change if the threat of an outbreak grows.

In the meantime, the committee recommended vaccinating certain state and local health and emergency workers on the front lines of disease detection and defense. That includes teams of doctors, nurses, and other disease workers who would be designated in advance.

The panel didn't specify how large the teams should be, but it did call for at least one team for every state, and multiple teams in populous states. Lab workers who handle the virus currently get the vaccine, which is administered by scratching the skin with a dosed fork-like device.

The panel also called for making the vaccine available to employees at a network of yet-undetermined hospitals designated to treat initial smallpox cases.

In all, the expanded immunizations would cover between 10,000 to 20,000 people, officials said.

Dr. Julie Gerberding, acting deputy director of the CDC, said the agency has sent its recommendations to Health and Human Services Secretary Tommy Thompson for review. If Thompson ultimately decides to adopt the guidelines, health officials will flesh out the details of the plan, including which hospitals would be receiving the vaccine. Gerberding said that process could take place over the "next months."

"We plan to move as expeditiously as possible so that we have a policy in place as more vaccine becomes available later this year, and as we continue to make sure America is properly prepared for any eventuality that may arise regarding bioterrorism," Thompson said in a statement.

Dr. John Modlin, a Dartmouth pediatrician and chairman of the panel, said the policy, if adopted, would be flexible. In the event of an outbreak, officials would review the recommendations "very, very quickly" and would most likely expand the number of people eligible for the inoculation.

Gerberding said that once the government has the infrastructure in place to distribute the vaccine, doses could reach anyone who needs them within 12 to 24 hours. The vaccine will always be voluntary, Modlin added.

The decision comes after months of debate over how to proceed in the post-Sept. 11, post-anthrax attack world. U.S. health officials have been stockpiling smallpox vaccine and will soon have 286 million doses, or enough to immunize every man, woman and child in the country.

The last case of smallpox in the United States occurred in 1948, and routine immunization against the disease ended here in 1972. The World Health Organization declared the virus eradicated in 1980.

But both the United States and Russia have stores of the virus, whose high kill rate and equally great fear quotient make it a prime candidate for a virus weapon. Terrorism experts have speculated that North Korea and Iraq may also possess the pathogen.

The specter of a smallpox attack gained some shape last week when a report surfaced about a deadly 1971 outbreak in the Soviet Union that was caused by the release in a field test of a "weaponized" strain of the germ. The virus killed three unvaccinated people and sickened seven others who had received the inoculation, suggesting that existing vaccines aren't amply potent against the strain.

When smallpox was rampant, the virus killed 30 percent of people infected. Some rare forms of the disease had death rates approaching 100 percent, according to the CDC.

The microbe has an incubation period of 10 to 12 days. During that time patients aren't infectious, but they become so after developing a rash and severe malaise. This period is of particular concern for disease officials, because anyone who comes within about six feet of an infectious patient can contract the deadly virus.

As a result, the CDC recommends quarantines and other methods of isolating patients to corral the disease. However, some scientists have questioned the value of quarantines, calling them needless and counterproductive. Still, Modlin said the agency's strategy of surveillance and containment "will almost certainly be successful in just about any attack scenario that could be envisioned."

One reason to avoid a return to mass inoculations is that the smallpox vaccine can cause rare but serious and potentially deadly side effects, especially in children and people with weakened immune systems.

"It's not as safe" as the other vaccines in the nation's preventive arsenal, Gerberding said. "It's special."

In addition to buying more doses of vaccine, the government has been working to boost the nation's supply of vaccinia immunoglobulin (VIG), the only known treatment for serious adverse reactions to smallpox vaccine. These include severe eczema and progressive death of skin around the area of the injection.

Late last year, the government said it had enough VIG to treat about 600 adverse reactions to smallpox vaccine. A report last June from the CDC predicted an overall complication rate of 108 cases per 1 million people re-vaccinated against smallpox. The number is roughly 11 times higher for those getting the shot for the first time.

VIG isn't recommended for most complications. But if tens of millions of Americans required immunization in the event of a smallpox threat, the current supply would be inadequate to treat the likely reactions for which it is effective.

David Neumann, director of the National Partnership for Immunization, said he agreed with the latest recommendations. "I believe that this is not the time or place for a universal" vaccination effort. "But it probably is prudent to make the vaccine available to first responders," said Neumann, who attended the two-day hearing as a non-voting participant.

Smallpox expert Dr. Bruce Polsky, chief of infectious diseases at St. Luke's-Roosevelt Hospital in New York City, said roughly 300 people might die of vaccine-related complications in a nationwide inoculation campaign. Without an actual case of the disease, Polsky said, that's too steep a price.

What To Do

For more on biological terrorism, visit the Center for Civilian Biodefense Strategies at Johns Hopkins University or the Sabin Vaccine Institute.

For more on the various bioterrorism weapons, try the American Medical Association.

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