The following is a Q&A on the topic with Dr. Arthur Reingold, professor and head of epidemiology at the University of California, Berkeley, School of Public Health, that was conducted by UC Berkeley Media Relations. Reingold will be heading the campus's new Center for Infectious Disease Preparedness, one of 19 academic centers for public health preparedness funded by the CDC. The center will provide training for frontline health and safety workers in the event of a bioterrorist attack or infectious disease outbreak.

Q: The CDC's Advisory Committee on Immunization Practices recently came out with recommendations to vaccinate 510,000 hospital workers against smallpox. Is vaccination the most effective way to protect ourselves against a bioterrorist attack with smallpox?

		'If we give the vaccine to 300 million people in the United States ... about one in a million people vaccinated will die from the vaccine. We're balancing known fatalities with this unknown, unquantifiable possibility of some mega-catastrophe.' —Dr. Arthur Reingold, professor of epidemiology

A: There are a substantial number of people who you wouldn't want to vaccinate, such as people who are immunosuppressed and people with eczema. This raises a question. If you say you're going to vaccinate healthcare workers, do they all have to be HIV tested before getting the vaccine? If they don't want to be HIV tested, presumably we're not going to vaccinate them. If they're not vaccinated, can they keep their jobs as healthcare workers in that facility?

Another whole issue has to deal with liability. Somebody is going to have to pay a lot of money if somebody dies from the vaccine. And what if somebody is injured or made very ill by the vaccine?

I think that as long as people are indemnified for serious injury and death, and as long as there is an appropriate way to deal with people who are immunosuppressed, then vaccinating health care workers is probably a reasonable thing to do.

Q: The side effects of the smallpox vaccine are frightening. They range from severe skin rashes to brain infections to death. How do you balance those risks against the threat of an attack?

A: I think everybody would agree that if somebody releases smallpox virus in the world today, it would be a worldwide public health disaster. I think it's also fair to say that if somebody released smallpox at JFK airport, among people getting on airplanes to hundreds of cities that day, we could have tens of millions of people dead a couple of months later because effectively no one in the world is immune to smallpox. It would be an unmitigated disaster - if it happens.

The problem is, the risk of someone unleashing the smallpox virus is unknown. It could be zero. But the people who worry about security issues will tell you they have reason to be concerned. They'll talk about how the facility in Russia had not been guarded very well and how some scientists who used to work there have not been accounted for and how others weren't paid for a long time. And who knows where they are now and what they took in their pockets? And who knows what some Iraqis have buried in some cave? Well, how do you respond to that? You can't argue and say that's not true.

One extreme view is that if we give everybody the smallpox vaccine, smallpox can no longer be an effective weapon against the United States because the overwhelming majority of our population will be immune.

But in the meantime, if we give the vaccine to 300 million people in the United States, we can give you a reasonable estimate that about one in a million people vaccinated will die from the vaccine. We're balancing known fatalities with this unknown, unquantifiable possibility of some mega-catastrophe. I'm not a policy person. I don't know how you make that decision.

The whole question of what to do about the smallpox vaccine has been a moving target now for some time, particularly in the past 12 months. Nothing about the science has changed in this interval. This discussion is being driven by politics. For example, in the paper, Vice President Cheney came out with a strong position about the use of the smallpox vaccine. Clearly when you're talking about the vice president of the United States wanting to see people vaccinated, you're talking about something that's based in large part on politics and not necessarily science or public health.

Q: Aren't there concerns about people who are vaccinated being able to spread the virus to others in close contact?

A: The smallpox vaccine is made from live vaccinia virus. We know based on studies before that some of the people we vaccinate can, in fact, transmit the vaccinia virus to people in close contact with them, particularly those in the same household.

The groups we're most concerned about in terms of the vaccine are people who are immunosuppressed, including HIV patients, people on chemotherapy and organ transplant recipients. Other people of particular concern are people with eczema, because those are people who historically have a substantially increased risk of adverse reactions to the vaccine.

So, in theory, unless there is a bioterrorism emergency, you would exclude from getting the vaccine anybody who's immunosuppressed, anybody who has eczema and probably anybody who lives in the same household with people with those conditions.

Q: Do you think the diluted form of the vaccine now being tested will be safer?

A: We think it'll still be effective, but there's no particular reason to believe it will be safer. After all, once the virus is injected into you, it multiplies. That's the whole point of a live virus vaccine. It multiplies up to the point that it stimulates immunity.

Q: Some fear that terrorists could easily alter a virus to make it resistant to the current vaccine. Last year, scientists reported that a genetically modified form of mousepox was vaccine-resistant and lethal. Is that a serious concern?

A: It's certainly possible to take a smallpox virus and modify it. Whether you can convert it to one against which the current vaccine doesn't work I think is completely speculative. The only laboratories that have the smallpox virus and are experimenting with it, as far as we know, are at the CDC in Atlanta, and a Russian facility. If the Russians have done that kind of work, they're certainly not talking about it.

If you really wanted to know the answer, you'd have to modify the virus, vaccinate some people, expose them to the virus, and see if the vaccine protects them. That's hardly an ethical study; you wouldn't have many volunteers signing up for that.

Q: What role will the new Center for Infectious Disease Preparedness at UC Berkeley play in implementing plans for smallpox vaccinations?

A: The center is meant to provide training to people working in frontline public health agencies to improve the capacity of people to do their jobs. I've already met with people in the California Department of Health Services who are working with the counties, under federal mandate, to develop the state and counties smallpox vaccination plan. Once they develop a plan, the center would help provide any necessary training for people to be well prepared to implement the plan.

But they're just starting. And they've got a lot of work to do.

Q: Given what you know now, would you vaccinate your family against smallpox?

A: If someone said, "Here's the vaccine, you make the decision about whether to vaccinate your family or not tomorrow," I would not vaccinate my children with the current smallpox vaccine. Am I really worried about the one-in-a-million chance that one of my kids will die from the smallpox vaccine? No. But I'm also not that worried about an outbreak of smallpox tomorrow or in the next year in California.