Some question need for child studies on risky smallpox vaccine

Friday, November 1, 2002

WASHINGTON -- Researchers want to begin the first studies of the effects of a risky smallpox vaccine on toddlers and preschoolers -- a proposal that is raising thorny questions about safety and ethics.

The vaccine is made of a live virus called vaccinia that can cause its own infections until the injection site scabs over, so researchers plan to keep inoculated children out of day care or school for a month. But will youngsters tear off their bandages and put relatives, playmates or others at risk?

And is it ethical to test in healthy children a vaccine that could cause a life-threatening reaction when they probably won't benefit from it -- unless a bioterrorist attacks with smallpox?

After research oversight boards had mixed reactions to the proposal, the Food and Drug Administration announced Thursday that for the next month it will accept public comment on whether the University of California, Los Angeles, and Cincinnati Children's Hospital should inoculate 40 2- to 5-year-olds with smallpox vaccine. They would be the first children to get the shots since routine vaccination ended in 1972.

Although wild smallpox was eradicated in the 1970s, officials fear that laboratory samples might have fallen into terrorists' hands. Faced with that uncertainty, the Bush administration is preparing to make vaccine again available, first to certain health care workers and later to the general public.

It's a difficult decision because of the vaccine's risks: Based on studies from the 1960s, 15 of every 1 million people vaccinated will suffer life-threatening reactions, and one or two of them will die.

A vaccinated person can spread the vaccine's virus by touching the injection site, then touching the eyes, mouth or someone else. If the virus spread to the eye, for instance, it could cause blindness. Someone with a weak immune system, such as an AIDS patient, could be killed by the virus.

Children once routinely got the smallpox shot, so why is new testing an issue?

The vaccine has been kept frozen for 30 years. To ensure there are enough shots to go around until new ones are made, scientists are studying if diluted doses work. Recent studies in adults suggested they do. The planned pediatric study, sponsored by the National Institutes of Health, would test those weaker doses in young children, whose immune systems work differently than adults' do.

"I would certainly want these trials to be conducted before I would want my child to be vaccinated," said Dr. Julia McMillan of Johns Hopkins University, a spokeswoman for the American Academy of Pediatrics. The academy has urged the government since last spring to do child studies before allowing broad access to the vaccine.

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