A Person's Smallpox Vaccine Risky for Others

By Warren King Seattle Times medical reporter
Sunday, January 19, 2003 - 12:00 a.m. Pacific

http://seattletimes.nwsource.com/html/localnews/134618388_smallpox19m.html

More than 800,000 people in Washington state - about one in seven residents - could risk a severe reaction from close contact with a person recently vaccinated against smallpox, combined estimates from health authorities and state officials indicate.

No one knows the actual risk of contact reactions among the vulnerable - - those with impaired immune systems or eczema and pregnant women. Studies from 40 years ago, when smallpox vaccinations were still routine, showed that for every 100,000 vaccinations, two to six people had severe reactions from having close contact with someone who was recently inoculated.

But authorities say the risks are higher now because many more people are living with vulnerable conditions.

Severe reactions in those at risk could range from a painful, widespread rash to death.

Concerns are mounting as state health officials hope to begin voluntary vaccinations of about 7,000 health-care workers in late February. They include public-health and hospital personnel who would treat the first patients in a smallpox outbreak.

The vaccinations, all voluntary, are part of the national plan to protect against a possible bioterrorism attack.

Coordinated by the Centers for Disease Control and Prevention (CDC), the project will offer vaccines to 500,000 hospital and public-health workers in the first phase of a large national campaign, and to 10 million additional health and emergency personnel such as firefighters and police in the second stage. Eventually, it will be offered to the public.

An advisory committee from the Institute of Medicine told the CDC Friday it should clarify the risks and benefits of the vaccinations and settle liability issues. The 15-member panel, most of them medical-school professors, said the second phase should not begin until the first phase has been completed and evaluated.

Smallpox vaccine is not given as a regular shot; instead, it is inserted into layers of the skin with repeated pricks of a small needle. The vaccination site is then kept covered until it heals.

Direct skin contact with secretions from vaccination wounds could set off the complications. That includes touching bedding, towels or clothing containing the secretions.

The secretions contain live vaccinia virus, a cousin of the smallpox virus that tricks healthy immune systems into building a smallpox defense. The vaccinia virus is the active component of the vaccine.

The vaccination sites are contagious for about three weeks, until the scab falls off.

Those who are vulnerable can contract severe "vaccinia," which is caused by the virus. That includes people who were previously vaccinated, but have one of the risk conditions. Secretions that touch healthy people could cause a limited rash that, if it gets into the eye, could cause permanent damage.

"We do not want to discourage people from getting health care because they are scared (of vaccinated workers) ... But we want them to know there are risks and that they should take the appropriate actions," said Judith Billings, chair of the Governor's Advisory Council on HIV/AIDS. The council plans a news conference this week to warn about the risks.

Health officials have detailed plans to insulate those who are vaccinated from contact with the vulnerable. That includes requiring special dressings and two layers of clothing over the wounds and not inoculating those who live with vulnerable people.

"We know who is at risk and our energies are on identifying who should not be vaccinated, including those who live with someone at risk," said Dr. Jo Hofmann, communicable-disease epidemiologist for the state Department of Health.

Tim Hillard, an advisory council member, said the group is "conservatively estimating" that about 500,000 Washington state residents potentially could have severe reactions from close contact with someone who has been recently vaccinated, including some who could suffer brain swelling and die.

No one knows exactly how many would suffer such a reaction because some people in a risk category might be somewhat protected. For example, some HIV patients have an adequate supply of certain defense cells that would protect them.

The numbers in the risk categories would become more important in a smallpox outbreak, when many people would need vaccinations quickly, said Dr. John Neff, a Children's Hospital & Regional Medical Center authority on contact vaccinia.

"It would be more difficult then to prevent contact with the vaccinated," said Neff, who had wide experience in smallpox-vaccination campaigns of the 1960s.

Using estimates from medical authorities and state health officials on the number of people in each at-risk category, The Seattle Times calculated that 800,000 to 1.6 million state residents could be classified as vulnerable. The estimates include state residents in these categories:

o Having eczema or atopic dermatitis, or anyone who has ever had one of these skin disorders: About 7 to 20 percent of the population has had the disease, according to experts. In Washington state, this would mean about 413,000 to 1.2 million people.

o Pregnancy: about 106,000 women a year become pregnant in the state and about 80,000 babies are born, but officials said they could not calculate how many are pregnant at any given time. Fetuses can contract vaccinia from their mother and it usually is fatal.

o Infants under age 1: about 78,000. The infants' immune systems are not fully developed.

o People with HIV: About 13,000 are infected with the virus, including those with AIDS. Experts estimate about one-fourth to one-third of those are not aware they are infected.

o Cancer patients: About 10,000 could be vulnerable because of immune suppression from cancer treatment or from certain forms of the disease itself.

o Transplant patients: About 4,000 to 5,000 solid-organ transplant patients are at risk because of immune suppression from drugs that prevent rejection of the transplanted organ.

o Elderly residents: No one knows exactly how many elderly might be vulnerable because of their naturally declining immune systems. However, experts estimate that a large percentage of those 80 and older are likely to be at risk. In Washington state, that's about 182,000 people.

Hillard said the group will emphasize in its warning this week that no one should stay away from hospitals because they fear infection from recently vaccinated workers. Instead, the council said, patients should ask the institution's policy for protecting them, and act accordingly.

"We're saying if you're immune-compromised, talk with your health-care provider," said Billings.

Warren King: 206-464-2247 or [email protected].

Copyright © 2003 The Seattle Times Company

April 5, 2008