A U.S. study confirms that babies have less risk of getting the flu when their mothers are vaccinated against the virus during pregnancy. The researchers analyzed data gathered from 2005 to 2014 from nearly a half million mothers and babies.

The flu virus is linked to complications such as premature births. Flu vaccinations in pregnant women help protect babies from catching the flu before they’re able to get vaccinated at 6 months old.

While only 10 percent of the mothers in the study said they got the flu vaccine during pregnancy, the children of those moms were more than 60 percent less likely to have flu symptoms and 70 percent less likely to have confirmed cases of influenza.

Salem Health doctors agree

Cheryl Lugenbill, MD, medical director of Salem Health Women’s and Children’s Services, was not part of the study, but agrees with its findings.

“This study clearly demonstrated the significant protection afforded to these babies when mothers were vaccinated during the pregnancy,” Dr. Lugenbill said. “We recommend that all pregnant women receive the flu shot to both decrease the risk of maternal influenza and protect their baby during the first months of life.”

Lisa Rice, MD, medical director of the Salem Health Obstetrics & Gynecology clinic, says part of the reason she recommends pregnant women get the flu shot is to impart immunity to their baby.

“Pregnant patients can get the flu vaccine at any point during their pregnancy — from the first trimester all the way until right before they deliver,” Dr. Rice said. “If a woman has not been vaccinated prior to delivery, we do try to vaccinate immediately postpartum as antibodies can be passed to the baby in breast milk.”

Flu endangers mother and baby

Dr. Leonardo Pereira — a maternal-fetal medicine specialist at Oregon Health and Science University who wasn’t involved in the study — tells Reuters Health that when pregnant women get the flu, they’re at increased risk for hospitalization, intensive care and death compared to women who are not pregnant.

“Non-vaccinated women who get the flu are also contagious and can infect other people in the community,” Dr. Pereira said.

The risk for catching the flu virus can appear before women leave the hospital after giving birth.

“When a mother who refused the flu vaccine delivers, her newborn baby is more likely to contract influenza and more likely to require hospitalization compared to babies born to mothers who were vaccinated during pregnancy,” Dr. Pereira said.