Infants born to mothers who received the flu shot while pregnant are only half as likely to be hospitalized for the flu as infants born to mothers who did not receive the vaccine.

A new study by Wake Forest Researchers found that infants are 45 to 48 percent less likely to be hospitalized with laboratory-confirmed influenza when their mother receives the influenza vaccine during pregnancy.

The Advisory Committee on Immunization Practice (ACIP) currently recommends yearly vaccination for anyone older than six months of age, and specifically targets certain groups, such as pregnant women, who have a greater risk of influenza-related complications.

However, this new research indicates that by receiving the vaccination, the mother is not only protecting herself – she is protecting her unborn child as well.

"It is recommended that all pregnant women receive the influenza vaccine during pregnancy because it is known that pregnant women have increased morbidity and mortality during pregnancy and in the immediate postpartum period if they get the flu," said Katherine Poehling, M.D., MPH., an associate professor of pediatrics and lead author on the study.

"We also know that mothers pass antibodies through the placenta to the baby,” she added.  “This study showed us that receiving the influenza vaccine during pregnancy not only protects the mother, but also protects the baby in the early months of life."

Infants less than 6 months of age have the highest rates of flu hospitalization of all children, according to Poehling, but the influenza vaccine is not licensed for or effective in infants that young.

Poehling said the new research should serve as a reminder to mothers-to-be and OB/GYNs as to how important proper vaccination is during pregnancy for both mother and child.

The study was published in American Journal of Obstetrics & Gynecology.