CDC says it's too soon to tell if anthrax vaccine increases risk of birth defects

Feb 14, 2002 (CIDRAP News) The Centers for Disease Control and Prevention (CDC) says it will take several months to determine if women in the US military who received anthrax vaccine in the first trimester of pregnancy had a greater risk of bearing children with birth defects.

In January, Department of Defense (DoD) officials said that a preliminary study suggested a possible link between anthrax vaccination in early pregnancy and birth defects. Because of this concern, the three service branches were ordered to step up screening efforts in order to prevent the vaccination of pregnant women.

But the CDC, in the Feb 15 issue of Morbidity and Mortality Weekly Report, says the data used in the preliminary study were too limited to justify any conclusions. "Review of preliminary data indicated important limitations in computerized medical records that preclude drawing conclusions from this preliminary study," the MMWR notice states. "Investigators are conducting a systematic evaluation of original medical records, including vaccination and infant health records. This evaluation will require several months."

The notice says that the anthrax vaccine used by the military has not previously been suspected to cause reproductive health problems, but no studies have been done, and the vaccine is not recommended or licensed for use in pregnancy. "DoD continues to maintain a policy of avoiding anthrax vaccination of pregnancy women," the report says. It adds that healthcare providers should continue to ask women if they are pregnant or intend to become pregnant and should not vaccinate those who are pregnant.

More than 500,000 military personnel have undergone anthrax vaccination since 1998. The vaccination program was greatly reduced in 2000 because of a shortage of the vaccine, caused in turn by the lack of Food and Drug Administration (FDA) approval of the recently renovated plant that produces the vaccine. The FDA approved the production operation in January, which is expected to ease the vaccine shortage.