A recent study by the Centers for Disease Control and Prevention (CDC) finds that when mothers receive the flu vaccine, their babies experience fewer hospitalizations and emergency room visits for the flu, particularly if the baby is under 3 months old or born to a mother who received the vaccine in the third trimester. Pregnant women are among those at higher risk of complications of severe illness from flu infection. Dr. Thomas Howell Jr., an OB-GYN at Mayo Clinic Health System, says it's not only important that those who are pregnant get a flu shot but also the people around them.