Fighting Smallpox. Or Not.

by Howard Fienberg
June 17, 2002

The Centers for Disease Control and Prevention (CDC) have organized public forums to discuss what to do about smallpox. There are some big questions that must be answered: Should the vaccine against smallpox be reserved only for critical emergency service people? Should they be required to take it? Should the vaccine be available to the general public? If so, should vaccination be mandatory?


Smallpox was a global scourge until its supposed global eradication in the seventies. It is fast (spreading with ease by inhalation or contact) and deadly (at least thirty percent of unvaccinated victims die). Plus, most experts believe that immunity has waned among people who were previously vaccinated (America stopped vaccinating when smallpox was though to be eradicated).


If you think that sounds horrific, you're right. So if a vaccine is available, why isn't everyone getting vaccinated?


For starters, we don't have enough of the stuff. The federal government has about 15 million doses in deep freeze storage, which can presumably be diluted into 75 million (without any loss in effectiveness). Drug maker Aventis Pasteur recently donated its frozen stockpile of 80 million doses. The feds are also purchasing 220 million doses made with an experimental technique, due by the end of the year. Officials expect to have as many as 300 million doses of the vaccine available by that time.


So why not vaccinate everybody when the vaccine is ready? Unlike most other vaccines, the smallpox one has some nasty side effects. Approximately 1 out of every 150,000 people vaccinated contracts severe infections (like encephalitis or brain infection) and another 1 in 500,000 people will die from the vaccine. So, if all 280 million Americans were vaccinated, over 500 probably die as a result. That's about a hundred times the number of people that died in our last brush with bio-terrorism, the anthrax attacks last fall. Suddenly, mass vaccination looks less appealing.


The CDC's standing policy for dealing with a smallpox outbreak shows no signs of changing. The CDC says no to pre-exposure vaccination. It prefers to wait until after exposure is confirmed, treat the victims, and then treat anyone who may have come into contact with the victims. This is know as 'ring containment.' Is ring containment a viable strategy?


Smallpox usually incubates in its victims for 10-12 days. During the last few days of incubation, the victims will experience fever and feel dreadful. When the incubation ends, the fever abates, but the victims are then infectious. The frighteningly glaring smallpox rash is at least 2 to 4 days in the future; in the meantime, the victims are unknowingly spreading the virus. By the time public health authorities are anywhere close to identifying the cases as smallpox, the disease has already spread.


And once you have the disease, you're in trouble. There is no "cure" for smallpox. We know that the vaccine works well pre-exposure, but evidence of post-exposure efficacy is only anecdotal. That anecdotal evidence points to the vaccine only working if the victim is inoculated within 4 days of contact with smallpox.


The crucial question in this scenario is: can we respond to a smallpox outbreak? While the CDC believes it can win the race against time, many outside of the institution heartily disagree. Dr. Richard Levinson of the American Public Health Association answers the question, "unequivocally, no." He cites the example of the West Nile Virus, which paralyzed the CDC and the whole of New York City's public health infrastructure. And that was all for an outbreak affecting less than a hundred people. Levinson does not expect the nation's infrastructure to be able to control the mass crisis that would hit after a smallpox outbreak.


Dr. William J. Bicknell of Boston University's School of Public Health, thinks it would be "virtually impossible" for public health officials to react within the necessary window of time. The ring containment strategy, which was used successfully to eradicate smallpox, works well when there are only a few cases amidst a mostly vaccinated population. But for a mobile populace with little or no immunity, the strategy just does not cut the mustard.


The largest problem is that smallpox is no longer a natural threat. That is why it is hard to have this debate, because we are dealing with a threat that may never come to pass. However, there are more than enough rumors of undesirable people and nations getting their hands on smallpox that we should consider it a viable threat. So knowing the threat, and that the ring containment strategy doesn't look too effective, vaccination becomes the next step. But at best, public health officials advocate vaccinating ... themselves. The New York Times (Jun. 7) reported that speakers at the CDC's forum in Manhattan, "many of whom were doctors, nurses and other health care workers, said they needed protection because, if an attack occurred, they would most likely be the first to care for patients."


You can't easily disagree with that argument. But what about the rest of us? Officials don't sound so reassuring when they claim that as long as they are inoculated, they will be able to take care of the rest of us. Smallpox is just too daunting a threat.


So should we open up the vaccine to every American? In our risk-averse society, it is not clear how citizens would react to a drug with such side effects when the threat is not staring us in the face. Levinson worries that with limited public interest and information (less than two hundred people turned out for the first two of the CDC's public forums), backlash against the vaccine could be severe. He cites the ongoing furor among parents who mistakenly link the Measles Mumps Rubella vaccine to children's autism.


At the same time, forced mass vaccination, which Levinson advocates, could bring an even harsher backlash. The U.S. military's attempts to inoculate our troops against anthrax spawned massive mis-information campaigns and a lot of refusals from soldiers who would rather leave the military than take the vaccine.


An alternative strategy would make the vaccine publicly available along with a strong effort to inform citizens of the risk of smallpox, as well as the risks inherent in the vaccine. While according to Levinson we could expect three hundred to six hundred deaths from the vaccine in a worst case scenario, that could be significantly cut by not vaccinating the most vulnerable groups: children and the immuno-comprimised (i.e. HIV/AIDS sufferers and chemotherapy patients).


It is time for a public debate, utilizing accurate scientific information rather than anecdotes, and in plain sight rather than in a few CDC hearings, is long overdue. Americans deserve to know the risks they face, whether they get the vaccine or not.

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