Vaccine Offer Raises New Questions

Sunday, December 23, 2001; Page A20

The Washington Post

by Valerie Strauss and Avram Goldstein

Federal health officials last week said that thousands of people who were exposed to high concentrations of anthrax spores should consider more preventive treatment, including an experimental vaccine, after they use up their 60-day supply of antibiotics. Here is information on the latest medical developments:

Q: What treatments are available to those who have been taking antibiotics for the past 60 days?

A: The Centers for Disease Control and Prevention is suggesting two options. The first is 40 additional days of antibiotic treatment. The second is the extra 40 days plus three doses of an experimental anthrax vaccine over four weeks.

Combining vaccine with antibiotics is the "best insurance" against developing anthrax, said Lt. Col. John Grabenstein, deputy director for clinical operations of the Defense Department's anthrax vaccine program.

A CDC video addressing questions concerning the vaccine, which is being shown to postal workers to help them decide on a course of action, is also available at www.sph.unc.edu/about/webcasts/2001-12-21_post

Who should consider additional treatment?

There has been conflicting information from different government officials. Individuals have been advised to consult their doctors.

CDC experts say workers thought to be at highest risk were those in buildings where the letters were opened, those who worked in facilities where others had fallen sick with inhalation anthrax -- particularly those who worked close to someone who became sick -- and those who know they inhaled large numbers of spores, such as some people in the Senate office building. CDC officials also say people are at higher risk if they worked in an area where a spore-laden envelope was sorted with mechanical equipment.

The U.S. Department of Health and Human Services estimates that about 3,000 congressional and postal workers in Washington, New York and New Jersey may still be at risk, but they are not sure.

Is anyone required to take the vaccine?

No.

Why does the CDC call the vaccine an "investigational product?"

The government says the vaccine has not been shown to treat infection after exposure to anthrax spores and is not approved for that purpose. If it works, the vaccine has not been shown to give long-term protection against anthrax.

Moreover, the Food and Drug Administration has not approved this particular lot because the drug maker's license to produce it is under review following a long series of failed inspections. However, CDC said this lot of vaccine passed all of the maker's internal tests for use in humans. Because this program is experimental, those who receive the immunization will be asked to participate in a two-year follow-up study.

Aren't vaccines supposed to be given before someone is exposed to an infectious disease?

That is how most vaccines work, but there are diseases treated with vaccine after exposure, such as rabies. The anthrax vaccine was developed for preventive use before exposure and has been used that way in the past by the military and by animal handlers who are more commonly exposed to anthrax found in nature.

What are the risks of taking the vaccine?

Grabenstein said vaccinations of 524,000 military personnel had found only low risks such as sore arms, aches and fevers with the rare serious reaction for 1 in 100,000.

Is this the way the military has used the vaccine? How long will it protect me?

Julie L. Geberding, acting deputy director for CDC's National Center for Infectious Diseases, said the way the vaccine is being offered -- three shots over a month -- is less than the military protocol of six injections over 18 months. The military approach is designed to confer longer-term immunity. The experimental approach offered is designed to help people fight off anthrax bacteria that may be present in the body -- not future exposures. "It's only to help with the current problem," Geberding said.

Why did federal officials decide now to recommend that certain people exposed to anthrax spores have the option of more treatment?

Some people potentially exposed to anthrax spores are completing their initial 60 days of antibiotics. The best available science indicates that spores can survive for up to 100 days in the lungs, and authorities fear that remaining spores could germinate and cause a potentially fatal infection. Exposure levels also appear to be higher than initially thought.

Also, officials last week disclosed that two weeks before the anthrax scare began in mid-October, government physicians on Capitol Hill met with officials from the FBI, the CIA and other agencies to prepare for an anthrax emergency. It was agreed then that vaccinations combined with antibiotics would be the best approach, according to John Eisold, the physician for Capitol Hill.

But in October there was not enough vaccine available, so only antibiotics were offered. Since that time, more vaccine has been obtained. However, D.C. government officials say they doubt there would be enough if everybody accepted the vaccine offer.

A few months ago, officials said anybody who had not contracted inhalation anthrax within 60 days of exposure was safe. Why have they changed their opinion?

Existing data from animal studies indicated that inhalation anthrax would be unlikely to develop beyond 60 days after exposure. So far, no cases have occurred in any of the 10,000 individuals advised to complete a 60-day antibiotic regimen or in thousands of people who disregarded the advice and quit the program -- including some who never took a pill.

But other animal research reviewed recently indicates that live spores may survive in the lungs beyond 100 days following exposure, raising the possibility that spores could cause anthrax after 60 days of antibiotics.

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