Military concerned over possible link between anthrax vaccine and birth defects

Jan 18, 2002 (CIDRAP News) – A preliminary study linking anthrax vaccinations in pregnant women with an increased risk of birth defects in their babies has prompted the US military to step up efforts to prevent immunization of pregnant women.

A study by the Naval Health Research Center of women who received the anthrax vaccine "identified a possible relationship between maternal anthrax vaccination in the first trimester and higher odds of birth defects," according to a Department of Defense (DoD) press release. The study has not yet undergone peer review, officials said.

In response to the data, William Wenkenwerder, assistant secretary of defense for health affairs, ordered the three service branches to devise plans within 2 weeks to strengthen screening efforts to prevent the vaccination of pregnant women. In his Jan 16 memo, Winkenwerder said screening efforts should include "careful questioning or other positive efforts, potentially including pregnancy testing when appropriate."

"Although these study results are preliminary and there are significant concerns about the database that require further investigation before any conclusions can be made, we are taking these steps to reaffirm our existing policies," Winkenwerder stated in the DoD press release. Officials said the DoD has a long-standing policy of avoiding immunization of pregnant women.

The study data are now being revalidated because they suggest that a number of women might have received the anthrax vaccine after the first trimester of pregnancy, the release said. That raises questions, because after the first trimester the women presumably would have known they were pregnant, an Associated Press report noted. That report said it was unclear whether pregnant women who received the shots were not asked about pregnancy or didn't know they were pregnant at the time.

At DoD's request, the Centers for Disease Control and Prevention will provide information about the Navy study in next week's issue of Morbidity and Mortality Weekly Report, DoD officials said.

About 525,000 military service members have received the anthrax vaccine since 1998. Some military personnel have complained of chronic health problems they believe are due to the vaccine. The vaccination program was cut back in 2000 because of a vaccine shortage.

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