Smallpox vaccine not for everyone

By Warren King
Seattle Times medical reporter

E-mail this article Print this article Search web archive

People vaccinated against smallpox could cause serious skin disease, or worse, if they come in close contact with those who aren't immunized, a Seattle researcher reported today.

The risk of spreading the disease, vaccinia, is not great, but those affected could suffer anything from a severe skin rash to death, Dr. John Neff, a Children's Hospital & Regional Medical Center scientist, and his colleagues say.

"We need to be extraordinarily careful in screening people, so we don't vaccinate those at risk and expose others at risk," said Neff, who had wide experience in smallpox-vaccination campaigns of the 1960s. Neff is principal author of a commentary in today's issue of the Journal of the American Medical Association.

The warning comes as the federal Centers for Disease Control and Prevention last month distributed guidelines for massive volunteer vaccinations in case of a bioterrorism attack with smallpox.

Some federal health officials have said the government should offer the immunizations to anyone who wants them, even in the absence of an attack. President Bush has not announced his decision about what strategy to use.

In June, federal officials also recommended vaccinations be offered to medical personnel and emergency workers who might be first exposed in an outbreak.

Studies from the 1950s and 1960s, when vaccinations were still routine, indicated the risk of vaccinia from contacts was about 2 to 6 per 100,000 vaccinations.

Data from that era also showed that among those actually receiving the inoculations, about 1 in 1 million were killed by the vaccine and 1 in 10,000 got serious skin infections or other ills.

Health officials would not knowingly vaccinate anyone at risk for complications, such as those with suppressed immune systems or pregnant women.

Neff and his colleagues said no one could predict the risk of contact vaccinia today. More people now have impaired immune systems and the skin condition eczema, both of which cause vulnerability.

Side effects from the immunizations are possible because the vaccine is made from a live virus, vaccinia, a relative of the smallpox virus that builds immunity against smallpox itself.

When someone is vaccinated, a sore forms at the site and oozes virus-containing pus for up to 19 days. It can be transmitted to another person through any break in the skin or through mucus membrane. Disease experts are now trying to develop a cover for the vaccination spot.

Contact with people with current or past eczema, an inflammatory skin condition characterized by itching, redness and scaling, can cause a severe, widespread rash, fever, scarring and even death in fewer than 1 percent, according to Neff. Young children, whose immune systems are still developing, are most vulnerable.

Those with impaired immune systems who are vulnerable include people with HIV infection, those undergoing cancer treatments, and organ-transplant patients.

The CDC recently estimated that 300,000 people in the U.S. are unaware they are infected with HIV, the human immunodeficiency virus. And pregnant women who get vaccinia can pass it to their fetuses, which usually are killed by it.

In the immune-suppressed, the disease at first is not painful, Neff said. But it quickly progresses, killing tissue and spreading down into the body, often fatally damaging solid organs. "This is the group in which it is most severe, most scary, most horrible," Neff said.

The researchers said "critical attention" must be given to screening and counseling vaccine candidates and their potential contacts to prevent vaccinia.

More will be known once immunizations of health workers and emergency workers are done.

Federal officials have said that could include up to 500,000 people, though they have not defined exactly who should be vaccinated. They also have not set a deadline for when the inoculations will be given, but some health officials speculate it will be by the end of this year.

Many health authorities, including Neff, have questioned the idea of offering voluntary vaccinations to the entire population. Given the adverse effects, they instead advocate inoculating health and emergency workers and a strategy of "ring vaccinations" for others: immunizations given to the close contacts of each infected person, and to the contacts of those contacts.

Warren King: 206-464-2247 or wking@seattletimes.com.