Q and A: Smallpox Vaccinations

The following is an interview with Dr. Sam Bozzette, lead author of the RAND study entitled, "A Model for a Smallpox-Vaccination Policy," published on the website of The New England Journal of Medicine on December 19, 2002, and in print on January 30, 2003.

Q. Does the RAND study support President Bush's smallpox policy?

A. The President said that the risk of a smallpox attack is low but not zero. Our study, which is designed to help policymakers understand the implications of various risk levels, agrees with the President's recommendations at this level of risk, and shows that the President's policy has a sound scientific basis.

The President ordered smallpox vaccinations for about a half-million people in the military, and recommended vaccination to civilian health care workers. He said the rest of the people in this country don't need vaccinations at this time. The President is saying that, given the low likelihood of a bioterrorist smallpox attack, vaccinating everyone could do more harm than good. For a low likelihood of attack, our study agrees.

Q. Why is vaccination of health care workers recommended?

A. Health care workers face the greatest risk of exposure to smallpox if this terrible disease is ever introduced to this country by terrorists or an enemy nation. Health care workers are exposed to sick people all day, every day. If health care workers themselves became sick, it could threaten our ability to keep our hospitals open and our health care system running. So it's prudent to vaccinate health care workers now.

Q. If every eligible health care worker were vaccinated, would there be any negative effect from the vaccine?

A. Our study shows that if nearly all the 10 million health care workers in the United States were vaccinated against smallpox, about 25 would die. That's because the vaccine is made with a live virus. Even if people with conditions known to make them vulnerable to vaccinia are excluded, a few people will react negatively—and it's likely that some will even die from the effects of the vaccine. However, if a smallpox attack were launched against the United States—and if no health care workers had been previously vaccinated—then up to 60% of all cases would occur in health care workers. Since health care workers face a much higher risk of exposure, the risk from the vaccine is worth taking.

Q. If everyone in the general population got vaccinated, what would be the result?

A. The positive result would be that, in the event of a bioterrorist smallpox attack, prior vaccination would be the most effective way of preventing the spread of the disease. However, there's a serious negative result too. As I noted previously, the vaccine is made with a live virus that can cause illness, even death, for some people. Our study estimates that if 60 percent of our total population were vaccinated for smallpox, about 500 would die, and thousands could suffer serious illness. If the likelihood of an attack directed against the general population is low, then it's just too risky to vaccinate everyone. That's why the President is recommending against general vaccination at this time.

Q. If people become sick and die from the vaccine, wouldn't that result in the spread of the smallpox virus?

A. No. The vaccine is made with a different virus that does not cause smallpox. The vaccine contains vaccinia virus, which is different but related to variola virus, the causative agent of smallpox.

Q. Do people in the military face a high level of exposure?

A. Our study focused on two groups: health care workers and the general population. We didn't specifically evaluate military personnel. But anyone watching the news or reading the paper has heard concerns that our military could be exposed to biological or chemical weapons if we go to war with Iraq.

Q. It's extremely difficult to predict what terrorists will do. Shouldn't we vaccinate everyone now, even at the risk of losing a few hundred people, to protect the general population?

A. The government is already acting on plans to protect the general population. The government is currently building stockpiles of smallpox vaccine, so that, in an emergency, we can launch a massive, nationwide vaccination program. Smallpox is not an instant killer. It takes weeks to become ill, and infected people cannot spread the disease until they become ill. So smallpox spreads slowly. Meanwhile, there's enough vaccine on hand for a widespread vaccination program.

Q. Are you planning to get vaccinated?

A. Yes. I decided to be vaccinated because I'm a health care worker—an infectious disease specialist. My wife, a pathologist, and my sister, a public health official, have both also decided to be vaccinated. But our children, parents, and other relatives not involved in health care won't be vaccinated, because, at the present time—to the best of our judgment—there's no substantial risk to them.

Related Links:

Widespread Smallpox Vaccination Is Too Dangerous