RSV Vaccination in Pregnancy Cuts Infant Hospital Stays

Maternal vaccination against respiratory syncytial virus (RSV) significantly lowers the risk of infant hospitalization, according to a new study led by researchers at the University of Pittsburgh and UPMC. The findings, published in JAMA Network Open, indicate that the RSVpreF vaccine reduces the risk of hospitalization in young infants by nearly 70%.

Among infants younger than three months, the vaccine demonstrated approximately 68% effectiveness against hospitalization for respiratory illness. It also showed 69% effectiveness against more severe lung infections caused by the virus.

Addressing a Critical Gap in Newborn Care

RSV is the leading cause of hospitalization among infants in the United States. According to the Centers for Disease Control and Prevention (CDC), about 2 to 3 out of every 100 babies younger than three months are hospitalized each year due to the virus.

In severe cases, infants may require mechanical ventilation or oxygen support. Until the FDA approved the RSVpreF vaccine in 2023, there was no reliable way to protect healthy newborns from RSV starting at birth.

Did You Know? According to the CDC, approximately 2 to 3 out of every 100 babies younger than three months are hospitalized annually due to RSV.

How Maternal Vaccination Works

The vaccine works by stimulating the pregnant person’s immune system to produce antibodies against RSV. These antibodies cross the placenta before birth, protecting the infant during their most vulnerable early months.

To ensure maximum protection, the vaccine is recommended between 32 and 36 weeks of pregnancy. Because the virus is seasonal, the CDC notes This proves typically administered between September and January in most of the U.S.

Expert Insight: Samantha Carter notes that the introduction of these tools represents a fundamental shift in pediatric preventative care. By moving from a period with no options to a dual-approach system—vaccination during pregnancy or antibodies after birth—clinicians now have the flexibility to protect newborns regardless of the timing of delivery.

Alternative Prevention and Future Research

For infants who are not protected at birth, monoclonal antibody treatment is available. Here’s typically used if the mother was not vaccinated or if the baby was born too soon after vaccination for antibodies to transfer fully.

University of Pittsburgh leading study to help prevent the flu in women

Clinical guidance generally recommends only one form of protection, as both are not typically needed together. Infants who receive the maternal vaccine at least 14 days before delivery generally do not require the separate monoclonal antibody shot.

Long-term Monitoring

This research is part of an ongoing four-year study. Researchers may continue to follow patients through the 2025-2026 and 2026-2027 RSV seasons to determine how long this protection lasts.

Future analysis is likely to expand to include infants up to 180 days old. This data could help policymakers and clinicians make more informed decisions regarding infant protection.

Frequently Asked Questions

How effective is the RSV vaccine given during pregnancy?
The study suggests it is 68% effective against hospitalization for respiratory illness and 69% effective against more severe lung illness in infants younger than three months.

When during pregnancy should someone get the RSV vaccine?
It is recommended between 32 and 36 weeks of pregnancy, typically between September and January, to allow antibodies to transfer to the baby before birth.

Does a baby still need an RSV shot after birth if the mother was vaccinated?
In most cases, no. If the mother was vaccinated at least 14 days before delivery, the infant typically does not need a separate monoclonal antibody.

How do you feel these new preventative options will impact the way families prepare for the arrival of a newborn?