What is known about the safety of influenza vaccines in pregnant women?
- Studies of several thousand pregnant women in the scientific literature have shown that inactivated seasonal influenza vaccines are safe during pregnancy. They have shown no evidence for harm to pregnant women, the pregnancy or to newborns of vaccinated women. In addition, FDA and CDC's routine monitoring of adverse events has not raised safety concerns.
- The FDA-approved Influenza A (H1N1) 2009 monovalent vaccines are made in the same licensed facilities and with the same manufacturing processes used to safely produce hundreds of millions of doses of seasonal influenza vaccine every year.
- In addition, before they can be used, all Influenza A (H1N1) 2009 monovalent vaccines must undergo the same rigorous FDA manufacturing oversight, product quality testing and lot release procedures that apply to seasonal influenza vaccines.
- Because of the scientific information in the literature, the fact that FDA-licensed manufacturers are producing the Influenza A (H1N1) 2009 monovalent vaccine following the same processes as for their seasonal influenza vaccines, and FDA-oversight of manufacturing, product quality testing and lot release procedures, FDA has a high degree of assurance of the safety of both seasonal and Influenza A (H1N1) 2009 monovalent vaccines for pregnant women.
- Potential side effects of the Influenza A (H1N1) 2009 monovalent vaccines are expected to be similar to those of seasonal influenza vaccines. The most common side effect is soreness at the injection site. Other side effects may include mild fever, body aches, and fatigue for a few days after the inoculation. As with any medical product, unexpected or rare serious adverse events may occur.
- The Influenza A (H1N1) 2009 inactivated (flu-shot) vaccines that have been licensed are available in both single dose and multi-dose preparations. Multi-dose preparations are formulated with thimerosal, a mercury-containing preservative used to ensure that the vaccine does not become contaminated after the vial has been opened. Single dose preparations contain no thimerosal, or only trace amounts. Studies have shown that there is no known harm from thimerosal preservative-containing vaccines. In 1999, FDA conducted a review of thimerosal in childhood vaccines and found no evidence of harm from the use of thimerosal as a vaccine preservative, other than local hypersensitivity reactions. The Institute of Medicine's Immunization Safety Review Committee reached a similar conclusion in 2001, based on a review of available data, and again in 2004, after reviewing studies performed after its 2001 report. Since then, additional studies have been published confirming these findings. Thus, pregnant women may receive either preservative-free or thimerosal preservative-containing influenza vaccine.
- All influenza vaccines continue to be produced using eggs. For this reason, a previous history of severe, life threatening allergies to eggs are a contraindication to the use of influenza vaccine.
Last Updated: 10/27/2009
