Growing evidence shows that flu vaccination during pregnancy is safe for mothers and their children, according to a July 10 editorial in the journal BMJ by Allen Wilcox, M.D., Ph.D., NIEHS Scientist Emeritus, and Siri Haberg, M.D., Ph.D., of the Norwegian Institute of Public Health.

Yet, in the 2017-2018 flu season, less than half of pregnant women in England were vaccinated. Comparable rates were found in the U.S. and Europe, noted Wilcox and Haberg. They addressed a new study, published in the same issue of BMJ, on the long-term safety of the flu vaccine for children exposed in the womb.

Mounting evidence

The authors of that study analyzed Canadian healthcare data for more than 100,000 women pregnant during the 2009-2010 flu pandemic and records of their children’s health up to 5 years of age. The researchers reported no elevated risk for cancer, infections, neurodevelopmental problems, or chronic diseases in the children of vaccinated mothers.

These findings are consistent with results from other, similar studies, according to Wilcox and Haberg. “The net result is a resounding lack of evidence for harm from flu vaccination in pregnancy,” they wrote.

A clear imperative

As a reproductive endocrinologist, Wilcox has authored more than 250 peer-reviewed journal articles and an influential book on fertility and pregnancy. (Photo courtesy of Steve McCaw)

The coauthors emphasized that findings about the benefits of vaccination during pregnancy require a strong response from the medical community.

“In our role as researchers, we are obliged to question the strength of the evidence, probe its weaknesses, parse its conclusions, and weigh its total contribution,” they wrote. “As physicians entrusted with the health of individuals and populations, we have a different role: When the facts allow, we are charged with speaking out loudly and clearly. Vaccination of pregnant women saves lives.”

Citations:
Haberg SE, Wilcox AJ. 2019. Flu vaccination in pregnancy. BMJ 366:I4454.

Walsh LK, Donelle J, Dodds L, Hawken S, Wilson K, Benchimol EI, Chakraborty P, Guttmann A, Kwong JC, MacDonald NE, Ortiz JR, Sprague AE, Top KA, Walker MC, Wen SW, Fell DB. 2019. Health outcomes of young children born to mothers who received 2009 pandemic H1N1 influenza vaccination during pregnancy: retrospective cohort study. BMJ 366:I4151.

(Marla Broadfoot, Ph.D., is a contract writer for the NIEHS Office of Communications and Public Liaison.)