SUSAN DENTZER: Let's paint a possible scenario that could happen here: a health care worker is vaccinated, then has contact with a patient who is immuno-compromised. Give us a sense of how in real life this could play out.
DR. OFFIT: Well, what this could mean is that we would take 5,000 hospitals and immunize as many as 100 people in that hospital. And those people are doctors and nurses and infectious control personnel, perhaps people who work in security and housekeeping -- many people who are coming in contact with patients on a daily basis.
Now, there are patients in the hospital, and certainly these days much more so than before, who are quite immuno-compromised, meaning that their ability to fight infections is much less than others. And that's true because we have many bone marrow transplant patients, we have solid organ transplant patients, we have HIV infections now in this country, which didn't exist 40 or 50 years ago. And so there's always the possibility that the nurse or physician may inadvertently transmit that virus to one of these patients, who are less capable of fighting off that particular virus, and in fact may be overwhelmed by it.
SUSAN DENTZER: Let's talk about the risks to the health care workers themselves, or to their family members, what could happen.
DR. OFFIT: Right. The healthy individuals who are receiving the vaccine for the first time are at risks of a number of things. And the risks are small, and they're in the sort of 1-2 per 100,000 vaccinee rate for the first vaccinee.
But they can get an infection of the brain, called encephalopathy or encephalitis. If they have eczema, they can have sometimes a severe and occasionally fatal disease called eczema vaccinatum. And this is very common that one can inadvertently touch the site that was inoculated and then touch the eye and have an infection of the eye, which can rarely be quite severe. In patients who have decreased capacities to fight infection, there is a disease called "progressive vaccinia" where in fact the disease is overwhelming and it is the cause of death.
So, there are side effects which are quite severe, which when you start to immunize as many as 500,000 people you're going to see. And what I think is sobering is that this is a vaccine which has eliminated disease, that was probably one of the most important causes of death in this world. Probably about 300 million people have died of smallpox. This vaccine has eliminated it.
When the disease occurs, either in epidemic or endemic fashion, this vaccine is a godsend. But we don't have smallpox disease anymore in this world. We haven't seen a case on the face of this earth in 25 years. And I guess my sense of this is that arguably one could wait until there's at least one case that's documented as being smallpox anywhere, frankly, on the face of the earth before we move forward to inoculate so many people with a vaccine that can do harm.
People hear the word, "vaccine" and they think "safe and effective." And that's true for the vaccines that we have today. But this vaccine has some serious side effects, and I'm not sure people are truly aware of that.
SUSAN DENTZER: And you have said that this is arguably the least safe vaccine we have.
DR. OFFIT: I think without question the smallpox vaccine has severe adverse events that occur at a rate far greater than any of the other vaccines that we use today. Which means that the smallpox vaccine, is I think, without question, our least safe vaccine.
But it is absolutely safe if one defines "safe" as benefits outweigh risks in a situation where the disease is present. When the disease isn't present, then one only is frankly aware of the risks, because there are no benefits.
SUSAN DENTZER: A change in what appears to be the developing government recommendation is that there will be some hint that after immunizing a core of health care workers and after immunizing an even much larger core of health care workers and emergency responders, that the vaccine could be made available to the general public on a voluntary basis. Is that a good idea?
DR. OFFIT: I think that it is not a good idea to make this vaccine available to the general public. The disease does not exist anywhere on the face of this earth, and what I am concerned about is that the public will not really understand what the side effects of this vaccine are, that the vaccine can cause serious adverse events that can lead to death, and that in the absence of disease, one can argue quite strongly that the risks of the vaccine outweigh its benefits.
Similarly there are some groups of people who are at greater risks of side effects from the vaccine -- people who have eczema or atopic dermatitis, people who have HIV infection but may not yet know it, people who are pregnant but may not yet know it, or those who get the vaccine and then become pregnant within four weeks. All are at either risks themselves, or at risk to the unborn child, of having harm come to them.
SUSAN DENTZER: And how many people nationwide are we talking about in all of those categories?
DR. OFFIT: It's estimated that if you look at people who have eczema or atopic dermatitis, or who have a history of eczema or atopic dermatitis, you could be talking about as many as 20 percent of the people in this country. There are about anywhere from 800,000 to 900,000 potential HIV-infected people in this country. And in terms of pregnancy, we have 3.5 to 4 million births a year. So you're talking about a fair number of people. But it's not only in the vaccinee.
Remember, the virus can be spread by contact. If you look previously at requests for something called "vaccinia-immune globulin," which is an antibody preparation that helps to some extent ameliorate the side effects of this vaccine, about 20 percent of requests for vaccinia-immune globulin in the past have been in contacts. So the contact also is at risk.
SUSAN DENTZER: Meaning the person who is somehow affiliated with the person who has actually been vaccinated?
DR. OFFIT: That's right. You're not just vaccinating those who are getting vaccinated. You're also vaccinating, to some extent, those who are coming in contact with those who are being vaccinated.
SUSAN DENTZER: So, just doing the math, the groups you sketched out earlier is the 20 percent of the population potentially in the eczema, et cetera, category -- pregnancy, HIV, AIDS. It sounds like that pushes up toward 100 million right there. And then you're saying all the people around those people, effectively. So, essentially, the whole population is to some degree vulnerable.
DR. OFFIT: I think that if you go by the guidelines as recommended by the Advisory Committee of Immunization Practices, to exclude people who have either themselves a history of eczema or atopic dermatitis or come in contact in their family with those people, or people who potentially have HIV infection or people who are pregnant or soon to get pregnant, I think you likely would eliminate about a third of potential vaccinees.
SUSAN DENTZER: Most public health officials have said: We have to accept the fact that large numbers of people could in fact die before we get a grip on what's going on [in the event of a smallpox attack] and before we have a chance to vaccinate at least the people who've been initially infected. That's what scares people, and that's what leads to this demand for vaccination on a voluntary basis. Is there nothing to that argument, or is that at least a plausible scenario?
DR. OFFIT: If you look at most infectious diseases, like chicken pox, or colds, or influenza, you will become contagious actually a couple of days before you get sick. That's not true with smallpox. With smallpox, by the time you're shedding virus or you're contagious, you already have a rash on your face, you already have fever, and you already are quite ill. So I think it's not quite the surprising infection that it is in terms of its capacity to be contagious as are some of these other infections.
So I think people will have a sense that they've been in contact with someone who is sick, and then once the first cases are identified, and then you can immunize communities. And I think that it will not be too late.
SUSAN DENTZER: But the first cases could be 100,000 people, of whom 30 percent or more could die.
DR. OFFIT: Again, I think that if you look at our capacity to eliminate smallpox from this earth, what we were to do is we were able to go around and say, "Here are five cases of smallpox. Let's find who all the contacts of these people are. Let's find out who all the contacts of the contacts of the people were." And by putting this sort of ring around those original cases, we were able to eliminate the disease in a fairly rapid manner. And I believe that if we knew who the cases were that came into this country, we would able to mobilize vaccine quickly enough to put a ring around the fire.
Now, would some people potentially die initially? I think the answer to that question is "yes." But remember with introducing the smallpox vaccine into this country at the level of several hundred thousand people, we also will cause serious adverse events, and I think we're likely to cause a death or two.
SUSAN DENTZER: You were the only person on the Advisory Committee of Immunization Practices who rejected that aspect of the proposal. So why is that no one else agreed with you?
DR. OFFIT: You'll have to talk to them.
SUSAN DENTZER: But you were in fact out there on your own.
DR. OFFIT: I think there are many people who share my concern that by immunizing a large percentage of health care workers, that we have the potential of causing serious adverse events and perhaps death, and that the risks of the vaccine may well outweigh its benefits. I think there are a number of people who share that concern.
SUSAN DENTZER: Where's the pressure coming from that's pushing mass vaccination on a voluntary basis?
DR. OFFIT: You know, there's an old Crosby, Stills, Nash, and Young song which starts, "If I'd ever been here before I would probably know just what to do." And the problem is that we've never been here before. And so we're taking our best, most educated and informed guess, and at the center of this is "Is this disease likely to come into this country? What evidence do we have that's going to come into this country?" I think if anybody knew exactly what that answer was, then we'd know exactly what to do. But we don't, and so we're taking our best guess. And with that, you're going to have a diversity of opinion.
My personal opinion is that I guess I'd like a little more evidence that the disease exists -- a single case anywhere on the face of this earth, I think can trigger then, an immunization program. But in the absence of that, I worry that we'll doing more harm than good. Now I'm sure ten years from now we're going to know exactly what the right decision was.