Controversy Surrounds Anthrax Vaccine

Medically Reviewed by Charlotte E. Grayson Mathis, MD on November 08, 2001
From the WebMD Archives

Nov. 8, 2001 -- A controversial vaccine with a history of manufacturing problems is the first line of defense in the war against weaponized anthrax. Is the anthrax vaccine safe? Is it effective? The answer depends on whom you ask.

Critics say the vaccine has been proven neither safe nor effective and may even be the cause of the mysterious group of ailments known as Gulf War syndrome that afflicts some soldiers. Government officials counter that there is no scientific evidence to back up that claim. They note that more than 500,000 U.S. troops have received anthrax vaccinations during the past three years, with less than 0.5% reporting even minor adverse reactions.

Supporters of the military's suspended program to vaccinate its 2.4 million active duty personnel and reservists say 18 separate studies show that the anthrax vaccine is safe. But an outspoken opponent of the program cites several others suggesting that short-term side effects are far more common than have been reported. Maine doctor Meryl Nass, MD, has studied anthrax for the past 13 years, and testified before Congress two years ago on the vaccine's safety.

"There are no data at all on long-term reactions," Nass tells WebMD. "The only long-term information we have is anecdotal. But the many, many anecdotal reports I have heard over the years suggest to me that long-term problems are common in those who receive this vaccine."

John F. Modlin, MD, who leads the government's Advisory Committee on Immunization Practices, agrees that there are still unanswered questions about the anthrax vaccine. Last December, the committee issued a report that, among other things, called for more studies into its safety.

At the time, the group did not recommend the routine vaccination of emergency workers and other so-called first responders who might be occupationally exposed in a bioterrorist attack. The committee wrote that, "at present, the target population for a bioterrorist attack of (anthrax) cannot be predetermined, and the risk of exposure cannot be calculated."

Modlin tells WebMD that the assessment of risk a year ago was very different from what it is today. He says the committee will revisit its recommendations on who should receive the vaccine. A CDC spokesperson says that meeting should take place soon.

"It may be that there is a wider group of people judged to be at occupational risk who we will recommend get the vaccine," Modlin says. "I don't want to speculate right now on who that would be. That is what we have to work out."

Manufacturing Woes

This week, the military announced that it will be giving anthrax vaccinations only to troops considered most at risk of a bioterrorism attack because its supply of vaccine is limited. And though health officials recently said criminal investigators, decontamination crews, and others working closely with anthrax investigations should be vaccinated, it is unclear whether that is happening.

No one is quite sure how much anthrax vaccine is available or will be available in the near future. That is because the FDA forced the sole U.S. manufacturer of anthrax vaccine to stop distribution two years ago after an inspection found 30 violations at the manufacturing plant. Those violations included vaccine safety and sterility problems.

BioPort Corp. of Lansing, Mich., has actually been making and stockpiling the vaccine again for over a year, but the reserves can not be used or distributed until it passes another FDA inspection. That could be as early as Thanksgiving, but there are no guarantees, officials say.

If BioPort does pass inspection, some 5.4 million doses of anthrax vaccine will be available for immediate distribution, Health and Human Services secretary Tommy G. Thompson said late last week. But Rep. Christopher Shays, R-Conn., who has held hearings on the anthrax vaccine, says it is unclear if the stockpiled doses are safe.

Military Discord

The anthrax vaccine used in the United States was developed during the 1950s and '60s and was licensed by the FDA in 1970. It is given as a series of six injections over 18 months and poses no risk of developing the disease because it is a killed vaccine.

Critics say there is no guarantee that the vaccine is effective against all strains of anthrax and that terrorists could conceivably manufacture vaccine-resistant strains to use as weapons. The only human study ever done in the U.S. evaluated the vaccine during an outbreak of anthrax among New Hampshire mill workers 40 years ago. It was found to be 93% effective in workers who got the vaccine, and studies in monkeys have shown similar rates of protection.

The main controversy surrounding the vaccine involves its safety, not effectiveness. Hundreds of military personnel have faced disciplinary actions since 1998 for refusing to take it, and about 50 have been court-martialed. The Government Accounting Office recently reported that a significant number of reserve and National Guard pilots have left the military rather than take the anthrax shots.

Nass says she has been contacted by many people in the military who blame the vaccine for chronic health problems. Most have been women, and most complaints have been symptoms such as chronic fatigue and pain, which are the same symptoms of several chronic diseases common in women such as fibromyalgia and lupus. There is no direct evidence that these symptoms are linked to the vaccine, however.

"The best information we have suggests that this vaccine is safe," Modlin says. "But a vaccine is only one means of protecting one's self from disease, and in this case there are other equally or more important things we can do. A vaccine is never going to be the answer to the problem. It is only one measure we can take to address it."