Flu Vaccine in Pregnancy Seriously Reduces Baby's Flu Risk

A new study shows that not only is the flu shot safe in pregnancy, it's crucial in helping your newborn stay healthy—until they're old enough to get their own.

Pregnant Woman Gets Her Flu Shot Image Point Fr/Shutterstock
Flu season may be just about over for now, but in just a few months it will be time again to make the decision: Should you get the flu vaccine? Google "flu shot" and you'll find lots of websites trying to scare pregnant women and parents away from vaccination. But the evidenced-based science is clear: The flu shot is safe, and it reduces your baby's chance of getting sick. A new study published in the journal Pediatrics is the latest in this research, showing that getting the flu shot in pregnancy will lessen your future child's risk by a whopping 70 percent.

Flu risk dropped with moms' vaccination

Researchers looked at all women who delivered from December 2005 to March 2014 at Intermountain medical facilities in Utah and Idaho, over 245,000 moms and almost 250,000 babies. Infants of women who got the flu shot while pregnant were 70 percent less likely to have laboratory-confirmed influenza, and were 81 percent less likely to be hospitalized for the flu in their first six months. Even more telling, 97 percent of confirmed flu cases occurred in babies whose mothers weren't vaccinated. "This large study over a long period—nine influenza seasons—further strengthens the evidence that when women are immunized against influenza during pregnancy, their infants are much less likely to be diagnosed and hospitalized with it," lead study author, Julie H. Shakib, D.O., M.S., M.P.H., assistant professor of pediatrics at the University of Utah in Salt Lake City, tells Fit Pregnancy.

To prove that the flu vaccine was actually causing these results instead of chance, the researchers compared the flu rates with rates of another illness, RSV (respiratory syncytial virus). The flu vaccine, as expected, had no impact on the number of cases of RSV. "Because our analysis found that the influenza vaccine had no effect on RSV diagnoses in infants, this supports the study finding that the benefits seen in the infants were actually due to the influenza vaccine their mothers received during pregnancy," Shakib says.

Protecting your baby against the flu

Because babies under six months are too young to be vaccinated themselves against the flu virus, they rely on the protection their mothers pass down while they're in the womb. "Women who are immunized against influenza during pregnancy provide maternal antibodies to their baby through the placenta," Shakib says, stressing this is the "best way" to protect vulnerable infants in their first months of life. Complications from the flu—which include pneumonia, dehydration and even inflammation of the brain—can be devastating for a young baby.

Even with the huge benefit for babies of getting vaccinated in pregnancy, an average of only ten percent of the expectant moms in the study got the flu shot. Part of this could be due to concerns over the vaccine's safety. "It is understandable that pregnant women may be concerned about harm, but they need to know that there is strong evidence that getting vaccinated against influenza during pregnancy is safe," Shakib says. "It protects both themselves and their babies from the serious complications of influenza." The study showed that more women began getting vaccinated during the H1N1 "swine flu" pandemic of 2009-2010, with the percentage rising from two to nearly thirty percent. Today that number has risen even further, but still, Shakib says, "only about half of pregnant women get the vaccine during pregnancy."

Free vaccines for pregnant women?

In addition to concerns about safety, many women in the study who did not get the vaccine were of a low socioeconomic level, or did not have good—or any—health insurance. Shakib hopes her study will show the scope of this public health issue in order to urge doctors and policy makers to better help women who might not have easy access to the vaccine. "All obstetric providers should both recommend and have the resources to provide the influenza vaccine to all pregnant women," she says. "Another practical intervention would be to provide free influenza vaccine to women who do not have insurance coverage."

The results of this large-scale study, along with recommendations from the American Congress of Obstetricians and Gynecologists (ACOG) and the CDC, should sway you toward getting the flu vaccine next season. A new one is developed every year, and although it doesn't protect against every strain of the flu, it does guard against those expected to be the most widespread in the coming season. In addition, make sure anyone coming into close contact with your baby, like grandparents, are vaccinated as well.

The flu vaccine is usually available as early as August, and it's best to get immunized by October if you can. Shakib hopes her study will help convince more pregnant women of its advantages. "We hope the results of our study will help support changes in practice and policy," she says.