Health

Smallpox Poses Deadlier Threat Than Anthrax, Experts Say

By CBSNews.com staff CBSNews.com staff

January 31, 2002 / 8:44 AM EST / CBS

Anthrax may be dominating recent headlines, but it's a different biological agent that has scientists worried: smallpox.

Experts say an attack using smallpox is unlikely, but the government is taking no chances. CBS News health contributor Dr. Bernadine Healy answers some questions about this highly contagious agent.

We've been focusing so much attention on anthrax lately, but you say smallpox is a much more potent biological agent. How is it different from anthrax?

Unlike anthrax, smallpox is highly contagious and can spread from person to person through the air. And, also unlike anthrax, it is very difficult to get a hold of. Smallpox was eradicated more than 20 years ago and no longer exists in nature or human populations. Officially only the United States and Russia have stocks of the virus, which are kept under tight security. But federal experts suspect secret supplies of smallpox exist, which is why they aren't taking any chances. Smallpox has killed more people through the ages than any other infectious disease--more than a half a billion in the 20th century alone.

What about the vaccine that we've heard about?

Right now there are between 7 and 15 million doses of the vaccine. Obviously, that is not nearly enough to protect all Americans, which is why officials are calling for new batches to be produced. They are also studying whether the existing supply can be diluted. Early results show that when the vaccine was diluted tenfold, it was about 70% effective. The vaccine also works unusually quickly. It can save a person even 3 or 4 days after the start of the viral infection.

Should everyone be getting vaccinated as a precaution?

Most government experts agree that's not necessary. Remember, the threat is very remote and the vaccine does have side effects that can kill or cause brain damage.

Many people are unaware of the smallpox symptoms. Let's go through them.

High fever.

Deep rashes.

Bloody sores.

Oozing postules.

People exposed to smallpox typically exhibit these symptoms in about 2 weeks. Once people have these symptoms, they can spread the virus. About one in three victims die, usually as a result of blood loss, cardiovascular collapse, or other infections.

Have there been any recent outbreaks? And if so, how did the government respond?

There was one in New York in 1947. A businessman admitted himself to a local hospital. Doctors initially thought he had a bad case of chicken pox. Before doctors realized that the man had it, he infected at least a dozen people. Health authorities responded by vaccinating or revaccinating 6 million people.