Smallpox: "We Eradicated It Before..."


By David Shook The threat of bioterrorism has galvanized the U.S. government. Suddenly, the development of new or improved vaccines to protect the mass of Americans from a possible biological attack is a top priority. After spending the past 25 years studying and developing vaccines, Vaxgen Chief Executive and scientist Lance K. Gordon has unique perspective on the urgent call for their use against anthrax, smallpox, or other pathogens that could be employed by terrorists, and their potential viability.

Gordon formerly headed Britain's Acambis, the company now working on a modern-day smallpox vaccine. Acambis is part of a wider effort to manufacture 300 million doses of smallpox vaccine to be available before yearend 2002. That could be a long wait, considering that a smallpox attack could kill one in three people exposed to the virus.

At Vaxgen, Gordon has been testing new HIV vaccines in several countries where AIDS is pandemic. He recently spoke with BusinessWeek Online Reporter David Shook about the threat of a bio-attack, what he's really afraid of, and why he thinks people shouldn't be too concerned about the recent spate of anthrax attacks delivered through the mail. Here are edited excerpts of their conversation:

Q: As a vaccine scientist, how do you view the government's sudden interest in getting the smallpox and anthrax vaccines into widespread production for the public?

A: It is certainly something that needs to be done post-September 11. But initially, the challenge will be to produce vaccines that we know to be safe and effective for the entire population. In the case of Vaxgen's AIDS vaccine, we're able to identify high-risk subpopulations on which we can do studies and identify the role of the vaccine and demonstrate whether it really works.

That's not possible with smallpox, which no longer exists in mankind. It might be possible to do human-challenge studies with the anthrax vaccine if you test it only against the cutaneous [far less lethal] form of the disease. But we'll never know if it works against pulmonary anthrax -- the much more deadly infection.

Q: While the present threat involves anthrax, people are more concerned long-range about a smallpox attack because that virus is so lethal and contagious. After smallpox was eradicated worldwide more than a quarter-century ago, what happened to the vaccination program?

A: In the U.S., the predominant vaccine was made using a strain of the virus called New York City Board of Health Strain. When smallpox was eradicated in the 1970s, we knew it worked well. So as the eradication program wound down, the U.S. government put in one last order to produce [several million doses] of the vaccine. The Centers for Disease Control in Atlanta still owns that reserve today.

The reason for [producing the reserves then] had nothing to do with terrorism. But there was always a chance that some isolated tribal clan still was infected by the virus somewhere, which could lead to another outbreak. And the virus is one of the most stable...so there was concern that with all the construction going on, someone might dig into mass graves where smallpox victims had been buried, unleashing it again. That's why we've kept a reserve. It's not nearly enough to inoculate everyone.

Q: Why did we stop vaccinating people?

A: There were side effects, but they were negligible compared to the benefit of the vaccine when smallpox was a problem. There are two ratios public-health authorities think about. One is the risk/benefit of a vaccine, the other is the cost/benefit. In the '70s after eradication, there was no risk of getting smallpox. That's why we stopped vaccinating. The benefit of vaccinating everyone was close to zero relative to the cost. That's the other reason we stopped.

In the wake of September 11, it seems the risk has certainly increased, and so has the benefit of vaccinating.

Q: Considering that the [smallpox] virus doesn't exist in nature anymore, does the threat of a smallpox attack concern you?

A: There are two acknowledged stores of the virus, in Russia and the U.S. There may be others that may have been retained elsewhere, but we don't know that for certain. The Russians admitted that they weaponized smallpox, so there's always the risk that some unknown medical research lab tucked away somewhere has a supply that could be used as a weapon.

But the one thing that makes it less of a concern, perhaps, than other forms of bioterrorism is that there is a mutual deterrent threat with smallpox. It's like nuclear arsenals during the Cold War. Smallpox knows no boundaries and cuts across all religions and walks of life. If terrorists are insane enough to not just kill themselves but also their mothers and children and the rest of their religion, then perhaps it might be used. Bottom line on smallpox, we eradicated it before. We could eradicate it again if we had to.

Q: What bioterrorism threat concerns you the most? What about the hemorrhagic fever viruses that are so deadly?

A: There are several of these viruses. The Venezuelan fever virus (VNHF) is the one that worries me the most. It's more common in animals, but it does break out in people, and when it does, it's highly contagious. It has the record for the most laboratory accidents because the virus is so difficult to control. It pops back every once in a while in South America and can be really nasty. The worst part about it is the nature of the disease. I won't get into the details, but it can lead to a horrible death. And there really isn't much in the way of antiviral drugs to fight it.

Q: What are your thoughts on the anthrax attacks in the U.S. this month?

A: Anthrax is not a contagious threat. If someday we have anthrax vaccine widely available with no side effects, then I'd get my family vaccinated. But right now a vaccine of that nature doesn't exist. Today we can immunize less than 1% of the population. It's just not available at this point.

Secondly, the current vaccine used by the military has some risks. It's a very old design and was never developed for widespread use. Given everything that has happened, however, I'm sure we're likely to see additional resources poured into a better vaccine.

But as for these attacks we've had with anthrax, if you open a suspicious package that may contain it, just hold your breath. Walk away from it. That's the best defense. Shook covers biotechnology issues for BusinessWeek Online. Follow The Biotech Beat every week, only on BW Online


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