Tuesday, November 1, 2011

Advisory Panel Urges U.S. to Conduct Controversial Anthrax Vaccine Trial in Children

by Jennifer Couzin-Frankel
on 28 October 2011, 4:42 PM

An advisory board to the U.S. Department of Health and Human Services this afternoon urged the U.S. government to launch a controversial trial of the anthrax vaccine in children. The 12-1 vote backs a September recommendation from a working group that spent about 3 months weighing the pros and cons of such a study and came out in favor of it.

Today's recommendation, by the National Biodefense Science Board (NBSB), isn't binding, and even if a study goes forward it will have to jump through many hoops before it can get up and running. That's because a trial like this one is almost without precedent in modern medical research: It involves giving children a vaccine that is almost certain not to benefit them, and that might harm them, all to protect other children from an unlikely scenario—a large-scale anthrax attack.

That said, "the science is clear that we need to do this," says Daniel Fagbuyi, the medical director of disaster preparedness and emergency management at Children's National Medical Center in Washington, D.C. Fagbuyi chaired the NBSB Anthrax Vaccine Working Group with seven voting members, all of whom are also part of the NBSB. The lone dissenter on the vote was Patricia Quinlisk, state epidemiologist and medical director of the Iowa Department of Public Health. Quinlisk chairs the NBSB and also sat on the working group, but said without elaborating that she could not support the recommendation.

The working group began considering a pediatric anthrax trial back in the spring at the government's request. The concern was that researchers have tested other vaccines given to children beforehand, to ensure that they're both safe and effective, but the anthrax vaccine never has been given to children. In a real disaster, medical personnel would be making decisions on the fly, uncertain whether children would react as adults do to the vaccine dose. For some vaccines, like tetanus, "the same dose is given to a 2-month-old infant and an NFL football player," says John Grabenstein, senior medical director for adult vaccines at Merck, who also sat on the working group and voted in favor of the recommendation this afternoon. Other vaccines, like hepatitis B and flu, are dosed differently in kids.

"For me, this decision comes down to, would I rather the first exposures [in children] occur before mass exposures or not, and I would," said Grabenstein during a conference call this afternoon prior to the vote. "I'd rather know what the response to the vaccine is before offering it to many, many, many thousands of children."

In adults, studies have suggested that the anthrax vaccine is quite safe; it's made with inactivated protein from the anthrax bacteria, much like vaccines that protect against diptheria and tetanus. Generally, however, studies in children must meet a higher standard than adult trials in protecting children from risk, particularly if the treatment has little chance of providing benefit. And that's where some worry that the proposed anthrax trial fails to meet ethical standards.

"I don't see how you can ethically do a study on a child where there is no chance the child benefits from that study," says Paul Offit, an infectious disease specialist at the Children's Hospital of Philadelphia in Pennsylvania, who often speaks out in favor of childhood vaccination. Offit attended one of the meetings of the working group and spoke out against a study. "I didn't prevail," he says.

Another big question is who would enroll their children in a clinical trial like this one. Fagbuyi, who served in Iraq as a U.S. Army Major and received the anthrax vaccine himself, says that some military members, first responders, and scientists working with anthrax—many of whom get the vaccine now—have expressed interest in having their children vaccinated, too. They may be comfortable volunteering them for an anthrax study, if it gets off the ground.

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