After decades of studies showing the flu vaccine to be safe for pregnant women, a new study is raising some doubt for women who have had multiple flu shots. A new study conducted at the Marshfield Clinic in Wisconsin and reported in the journal Vaccine has shown an association between women getting a specific type of flu vaccine two years in a row and miscarriage. Given the limitations of the data and the relatively small number of women in the study, however, it is too early to know if the results reflect a real biological association between vaccination and miscarriage, or if the women in the study who miscarried did so for other reasons.
Guidelines aren't likely to change
Current flu vaccine guidelines recommend that women receive flu vaccines during pregnancy, regardless of the trimester. Influenza can itself cause birth defects and miscarriage, and so it would be difficult for experts to change the guidelines based on one study that contradicts other studies on the same topic that have come before it. Additionally, it's not clear if the women who miscarried may have also had other risks, such as the fetus having a genetic abnormality that could have contributed to the miscarriage.
No sudden moves
In short, pregnant women should not panic about this result and forego the flu shot. The study shows an association between miscarriage and sequential flu shots of a particular type, but the reasons for the association are not clear, nor is it clear that not getting the flu shot is any less risky than getting it.
This study raises questions, however, and follow-up studies will be important to watch. Vaccines are supposed to be safe and protective, not cause harm in and of themselves. Those who have been injured by vaccines have recourse for compensation, however, and should contact an experienced vaccine injury lawyer.