In the Journals: Influenza Vaccine and Spontaneous Abortion during the First Trimester
Published on in Vaccine Update for Healthcare Providers
Published on in Vaccine Update for Healthcare Providers
In September 2017, James Donahue and coworkers from the Vaccine Safety DataLink reported the results of a study examining the risk of spontaneous abortion following receipt of inactivated influenza vaccine during pregnancy (Donahue JG, Kieke BA, King JP, et al. Association of spontaneous abortion with receipt of inactivated influenza vaccine containing H1N1pdm09 in 2010-2011 and 2011-2012, Vaccine. 2017 Sep 25;35(40):5314-5322.)
The authors found that the incidence of spontaneous abortion in the vaccinated group was indistinguishable from the unvaccinated group in the second and third trimesters. However, a statistically significant increase in spontaneous abortions was observed in the vaccinated group in the first trimester. For many reasons, this result appears to be anomalous:
Because of the limitations of this study, the authors concluded, “This study does not and cannot establish a causal relationship between repeated influenza vaccination and SAB [spontaneous abortion].” Unfortunately, the media as well as several articles on the internet referred to this finding as a “signal,” scaring parents unnecessarily.
Contributed by: Paul A. Offit, MD
Categories: Vaccine Update September 2017, In the Journals
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