December 18, 2023

Flu Vaccination during Pregnancy Decreases Flu Hospitalizations and Emergency Department Visits in Infants after Birth

A new Centers for Disease Control and Prevention (CDC) study shows that infants younger than 6 months born to pregnant people who were vaccinated during their pregnancy were protected from flu-related emergency department visits and hospitalization. Infants in this age group are at higher risk of being hospitalized compared to other children and cannot get a flu shot until after they turn 6 months. 
This study highlights the importance of pregnant people getting vaccinated since both pregnant people and their infants are at higher risk of being hospitalized with flu. CDC urges healthcare providers to recommend flu vaccine to their pregnant patients. 

The CDC study published in JAMA Pediatrics looks at data from the New Vaccine Surveillance Network (NVSN) from the 2016-2017 through the 2019-2020 flu seasons, finding:
  • Flu vaccination during pregnancy reduced the risk of flu in infants younger than 6 months by one-third.
  • Vaccine effectiveness during pregnancy increased with the severity of infant disease, reducing the risk in infants of emergency department visits by about 20 percent and reducing the risk of hospitalization by about 40 percent.
  • Protection was greatest among infants younger than 3 months, reducing the risk of flu-related hospitalizations or emergency department visits by half.
  • Vaccine effectiveness was higher in infants born to people who were vaccinated later during their pregnancy.
Getting a flu vaccine during pregnancy can protect both the pregnant person and infant from flu and flu-related hospitalizations. Vaccination during pregnancy provides the infant with critical protection from flu for several months after birth because the pregnant person passes antibodies to their developing fetus. Influenza virus infection during pregnancy is associated with an increased risk of hospitalization, and some studies have found an association with adverse birth outcomes. According to CDC data systems, flu vaccination among pregnant people is concerningly low and has fallen by 10 to 15 percentage points since the COVID-19 pandemic. A previous study has shown that flu vaccination during pregnancy reduced the risk of flu illness in pregnant people by about half. This estimate was similar to other estimates of flu vaccine effectiveness in adult populations during the same season. Flu vaccines are safe and effective. CDC and Advisory Committee on Immunization Practices 2023-2024 Flu Vaccination Recommendations advise pregnant people to get vaccinated during any trimester of pregnancy.

As a healthcare provider, your strong recommendation and offer of vaccination are key factors in whether your patients get vaccinated. Use these data to support strongly recommending flu vaccination for your pregnant patients. There’s still time for pregnant patients to get vaccinated against flu for the best protection during the 2023-2024 flu season.

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