02/02/2003

BY FELICE J. FREYER
Journal Medical Writer

As states and counties around the country move forward with plans to vaccinate as many as 500,000 health-care workers, voices from the medical community and labor are urging caution.

So far, 28 states and two counties, including Rhode Island, have received smallpox vaccine from the U.S. Centers for Disease Control and Prevention. Rhode Island plans to vaccinate some 30 health-care workers in the last week of this month, and then move on to an additional 1,200.

But the largest nurses' unions in Rhode Island and Massachusetts have urged their members not to participate. An article in last week's New England Journal of Medicine said that mass vaccination against smallpox could cause more deaths than an outbreak of the disease.

And the Institute of Medicine, a branch of the National Academy of Sciences, recently called on the Bush administration to take time to evaluate the current vaccination effort before moving on to a larger group.

Here are answers to questions raised by the controversy.

Q: People get vaccinated all the time. Why all the worry about the smallpox vaccine?

The vaccine differs from the commonly used vaccines for measles, influenza and other diseases in several respects.

Smallpox does not exist in nature. The disease, which afflicts only humans, was eradicated 25 years ago through a worldwide vaccination program. Laboratory samples of the smallpox virus, however, may have fallen into terrorists' hands, and it is feared they could be used in a biological attack.

But it is not known whether such an attack will ever occur, nor whether it would be successful in making many people sick. There is a known risk of measles or hepatitis, for example, making vaccination against such illnesses a logical choice. But the risk of smallpox is unknown, making the choice much more difficult.

At the same time, the smallpox vaccine causes more health problems than other vaccines, and most medical professionals practicing today have no experience coping with its side effects. And, unlike most other vaccines, it uses a live virus that a newly vaccinated person can transmit to someone else.

Q: What happens when you're vaccinated against smallpox?

The person vaccinating you takes a two-pronged needle, dips it in the vaccine and then pricks the skin 15 times, usually on the upper arm. The pricking causes a sore spot, and in three or four days a red, itchy bump develops. In the first week the bump becomes a large blister, and in the second week, a scab forms.

During this time, many people will experience fever, malaise, muscle pains or rashes. About a third of the people vaccinated will feel badly enough to need a day off from work.

When the smallpox vaccine was routinely administered (up until 1972), a tiny number of people, between 14 and 52 out of every million vaccinated, became severely ill, and 1 or 2 per million died from vaccine reactions. The people most likely to have complications are those who have had skin conditions such as eczema, and those whose immune systems are weak, such as people who have HIV, are undergoing chemotherapy for cancer, have had an organ transplant, or take steroids to suppress the immune system.

The government plan calls for screening out people with those conditions, as well as barring pregnant and breastfeeding women, and children under 18. In Rhode Island, volunteers will be required to take free, confidential HIV tests, and pregnancy tests.

But there are many more people with compromised immune systems today than when the vaccine was routinely used. And all the risk factors for complications are not known.

Also, during a two-week period after inoculation, vaccinated people can infect others.

Q: Why is the vaccine infectious?

The smallpox vaccine uses a live virus known as vaccinia. Vaccinia does not cause smallpox, but it provides immunity to smallpox because it has a similar chemical structure.

Until the scab falls off the lesion at the vaccination site, vaccinia can be spread to others through contact with the sore or pus from it. But if the lesion is kept covered, and the vaccinated person washes his or her hands regularly, the risk of transmission is considered negligible.

To protect against transmission of vaccinia in hospitals, the Rhode Island Health Department plans a two-stage approach to its vaccination effort. Two or three volunteers from each hospital will serve as "vaccine monitors." They will be vaccinated first, probably during the last week of this month, and then they will take responsibility for monitoring the vaccine lesions of the volunteers who come after them.

But if the vaccine were ever offered to a wider group of people, it would be much harder to control the spread of vaccinia. Some experts worry that mass vaccination would lead to vaccinia infections in children and other vulnerable people.

Q: What is smallpox like?

Smallpox starts with high fever, head and body aches, and sometimes vomiting. Then the body is covered with pus-filled blisters that crust, scab and fall off after about three weeks.

There is no treatment for smallpox, and about 30 percent of its victims die. Survivors are left scarred and sometimes blind. No question, smallpox is worse than the vaccine, and that's why vaccination was recommended until the disease was eradicated.

The last case of smallpox in the United States was recorded in 1949, and the last case in the world was in Somalia in 1977.

Q: If smallpox were introduced, would it spread rapidly in the population?

Many experts think not. An infected person is not contagious until he or she has an active rash, which is a horrendous, unmistakable sight. When contagious, a person is extremely ill and unlikely to be roaming about. Smallpox is spread by close face-to-face contact, and only rarely through the air.

If someone is exposed to smallpox, there's a window of one to three weeks before that person becomes infectious. The vaccine can be administered then, and it will most likely keep the exposed person from getting ill.

Smallpox was eradicated by locating, vaccinating, monitoring and -- if symptoms developed -- isolating every person who came in contact with a smallpox victim. This same approach could be used if smallpox were re-introduced.

Q: If the vaccine works even after you've been exposed to smallpox, why get it ahead of time?

You get better protection if you're immunized ahead of time rather than after exposure. Also, the vaccine doesn't always "take" on the first try.

For health-care workers, the advantage to getting vaccinated ahead of time is that they will have already gone through the process, ensured that the vaccine "took," and recovered from any malaise the vaccine caused, before being confronted with smallpox victims needing their care. Whether that advantage is worth the risk is an individual decision.

Q: What are the nurses' unions concerned about?

They're worried about vaccine reactions and the possible spread of vaccinia to patients. They also think it's unwise for health-care workers to risk getting the vaccine until they know who will pay for their care and compensate them if they become ill. It's not clear whether workers' compensation or the individual's health insurance will pay for any medical care and sick leave resulting from vaccine complications, or whether there will be any other compensation.

Q: Are people who received the vaccine as children before 1972 still protected?

Probably not. The vaccine's protection is thought to wear off after three to five years. But, those who have been previously vaccinated are less likely to have a bad reaction to a second vaccine.

Q: Can anyone who wants it get vaccinated against smallpox?

No. The vaccine is not currently available to the general public, but the government has ordered enough to vaccinate everyone in an emergency. If there were a smallpox case in Rhode Island, the Health Department could obtain vaccine within 12 hours.

A few Rhode Islanders who met eligibility requirements have been vaccinated through a study comparing the original vaccine with a new version. For more information on this study, call Memorial Hospital of Rhode Island at 729-2616.

For more information, try the U.S. Centers for Disease Control and Prevention, www.cdc.gov, or the Rhode Island Department of Health, www.healthri.org/topics/smallpox.htm

Read the state's full plan for preventing smallpox, and find out more about the disease itself at:

http://www.health.state.ri.us/environment/biot/smallpoxprepare.htm