Possible Link Between Flu Vaccine and Miscarriage

The CDC is clear in its guidelines that pregnant women in any trimester of their pregnancies should get the flu vaccine.

The CDC noted that an ongoing study is looking at miscarriage risk among women who were eligible to get the flu shot during the 2012-13 and 2014-15 flu seasons, but the results are not expected until late next year.

The U.S. Centers for Disease Control and Prevention, which funded the new study and had a presentation on the data in June 2015, posted a website update that said it "has not changed the recommendation for influenza vaccination of pregnant women".

This study focused only on miscarriages, which occur in the first 19 weeks of pregnancy and are common. Only four of the comparable 485 healthy pregnancies had involved women that were vaccinated in that manner. The researchers tried to make statistical adjustments to level out some of those differences but some researchers don't think they completely succeeded.

"We only saw the link between vaccination and miscarriage if they had been vaccinated in the season before", said James Donahue, an epidemiologist and lead author.

Two other medical journals rejected the article before a third, Vaccine, accepted it. Dr. Gregory Poland, Vaccine's editor-in-chief, said it was a well-designed study that raised a question that shouldn't be ignored.

"Some people may experience some cold like symptoms depending on their immune system but get the flu shot no matter what unless you have some religious or moral reasons not to". Of the women who miscarried, 17 had received flu vaccine in the 28 days before the miscarriage, and had also been immunized the prior flu season.

Though this study may cause worry and confusion, it is evidence "of just how rigorous and principled our vaccine safety monitoring system is", said Jason Schwartz, a Yale University vaccine policy expert. As a result of the 2009 H1N1 swine flu pandemic that killed hundreds of thousands of people around the world, including more than 12,000 in the United States, vaccine manufacturers developed vaccines to protect against the new H1N1 strain, which was different from viruses that circulated before 2009.

The Ohio Department of Health doesn't track flu deaths for adults 18 years of age or older but says a handful of children died from it last year.