Study Finds RSV Vaccination During Pregnancy Sharply Reduces Hospitalization in Infants

The risk of hospitalization in young infants was slashed by nearly 70% when pregnant mothers were vaccinated for RSV.

June 5, 2026

2 min read

Key Highlights

- Maternal RSV vaccination reduces infant hospitalization risk by nearly 70%.
- Effectiveness is approximately 68-69% for infants under 3 months old against RSV-related illnesses.
- RSV is the leading cause of hospitalization among infants in the U.S., with 2-3% of babies under 3 months affected annually.
- The study compared outcomes between infants of vaccinated and unvaccinated mothers, excluding those who received post-birth monoclonal antibody treatment.
- Both maternal vaccination and post-birth monoclonal antibody treatments are effective, but generally not used together.

A study published in JAMA Network Open found that vaccination against RSV during pregnancy “reduced the risk of hospitalization in young infants by nearly 70%.”

The study shows that “administering one dose of the maternal RSV vaccine (RSVpreF vaccine) reduces hospitalization related to RSV in young infants. The results are consistent with findings from RSVpreF vaccine clinical trials.”

Among infants under 3 months old, “maternal vaccination was associated with approximately 68% effectiveness against hospitalization for respiratory illness caused by RSV, and 69% effectiveness against more severe lung infections also caused by the virus.” RSV is the leading cause of hospitalization among infants in the U.S.; about “2 to 3 out of every 100 babies younger than 3 months are hospitalized each year due to RSV, with severe cases sometimes requiring oxygen support or mechanical ventilation.”

Researchers focused on “infants who were tested for RSV and compared outcomes between those whose mothers received the vaccine during pregnancy and those whose mothers did not. Infants who received monoclonal antibody protection — a separate RSV prevention option administered after birth — were excluded.” Infants who are not protected at birth can “receive a monoclonal antibody treatment after birth to prevent RSV. Clinical guidance recommends that infants receive one form of protection; both are generally not needed together.”