St. Louis, June 18, 2007 St. Louis researchers have identified common DNA variations that underlie susceptibility to fever after smallpox vaccination. Their finding is the first to link individual differences written into the genetic code with a vaccine-related complication albeit a mild one.

Most of the eight genetic alterations the scientists identified increased the likelihood of fever after smallpox vaccination. A few, however, reduced fever risk. The research, led by scientists at Washington University School of Medicine in St. Louis, will be published in the July 15 issue of The Journal of Infectious Diseases and is now available online.

The studys results raise the possibility the same genetic variations linked to fever following smallpox vaccination may also influence fever risk after other live-virus vaccines, including the one for measles, mumps and rubella. This so-called MMR vaccine is routinely administered to small children, and fever is a bothersome and common side effect.

Eventually, the authors say, it may be possible to develop a test that predicts which patients are at risk for vaccine-related fevers. Such a test also may help doctors anticipate and prevent more serious complications linked to the vaccines.

Vaccines are extraordinarily safe and effective, but that doesnt mean we cant try to make them even more acceptable by discovering ways to further reduce the chance of adverse events, including minor ones like fever, says the studys lead author, Samuel Stanley Jr., M.D., vice chancellor of research at Washington University and a professor of medicine and microbiology. The research was funded by the National Institutes of Health through a grant to the Midwest Regional Center of Excellence for Biodefense and Emerging Infectious Diseases Research (MRCE), which Stanley directs.

Routine smallpox vaccinations in the United States were halted in 1972, when the disease was considered eradicated in this country, but
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Contact: Caroline Arbanas
arbanasc@wustl.edu
314-286-0109
Washington University School of Medicine
18-Jun-2007