Maternal RSV Vaccine Significantly Reduces Infant Hospitalizations

Maternal vaccination against respiratory syncytial virus (RSV) during pregnancy provides strong protection for infants against severe respiratory illness, according to recent data from the UK’s maternal RSV vaccination program and clinical guidance from the U.S. Centers for Disease Control and Prevention (CDC). The vaccine, administered as a single dose between 32 and 36 weeks of pregnancy, helps transfer protective antibodies from mother to infant, reducing the risk of hospitalization due to RSV in the first six months of life.

How Maternal RSV Vaccination Protects Infants

RSV is a leading cause of lower respiratory tract disease in infants worldwide, often resulting in bronchiolitis or pneumonia that requires hospital care. Vaccinating pregnant individuals enables the transfer of RSV-specific antibodies across the placenta, offering passive immunity to newborns during their most vulnerable period.

According to the CDC, pregnant women should receive a single dose of the maternal RSV vaccine (Pfizer’s Abrysvo) during weeks 32 through 36 of gestation to maximize antibody transfer and protect their infants from severe RSV disease. This timing aligns with peak antibody production and placental transfer efficiency.

Evidence of Effectiveness from Real-World Programs

Early data from the UK’s maternal RSV vaccination program shows substantial effectiveness in preventing severe disease and hospitalizations in infants. Experts emphasize that administering the vaccine as early as possible within the recommended 32-to-36-week window maximizes protection.

In England, maternal RSV vaccine uptake has increased from 55 percent during the initial study period to 64.1 percent by November 2025, reflecting growing acceptance and access to the immunization.

FDA Approval and Clinical Guidance

The U.S. Food and Drug Administration (FDA) approved Abrysvo in August 2023 for use in pregnant individuals to prevent lower respiratory tract disease and severe lower respiratory tract disease in infants from birth through six months of age. This marked the first vaccine approved specifically for maternal immunization against RSV.

The FDA had previously approved Abrysvo in May 2023 for the prevention of RSV-related lower respiratory tract disease in adults aged 60 years and older.

Clinical guidance from the CDC reinforces that a single dose of any FDA-licensed RSV vaccine is recommended for all adults aged 75 and older, as well as adults aged 50–74 who are at increased risk of severe RSV. Individuals who have already received one dose should not receive another at this time.

Key Takeaways

• Maternal RSV vaccination during weeks 32–36 of pregnancy significantly reduces infant hospitalizations due to RSV.
• The vaccine works by transferring protective antibodies from mother to infant, providing passive immunity in early life.
• Real-world data from the UK shows strong effectiveness in preventing severe RSV disease in infants.
• Vaccine uptake in England rose to 64.1 percent by November 2025.
• The FDA-approved Abrysvo vaccine is recommended as a single dose during pregnancy to protect infants through their first six months.
• Adults aged 75 and older, and those aged 50–74 at increased risk, should also receive a single dose of an RSV vaccine.

Frequently Asked Questions

When should pregnant individuals obtain the RSV vaccine?

Pregnant individuals should receive one dose of the RSV vaccine between 32 and 36 weeks of pregnancy to optimize antibody transfer to the fetus.

Is the RSV vaccine safe during pregnancy?

Yes. The FDA and CDC have determined that Abrysvo is safe and effective for use in pregnant individuals when administered during the recommended gestational window.

How long does protection last for the infant?

Antibodies transferred from the mother provide protection against severe RSV disease from birth through approximately six months of age, which is the period of highest risk for severe outcomes.

Can someone who was vaccinated in a previous pregnancy get the vaccine again?

No. Current guidance states that adults who have already received one dose of an RSV vaccine should not receive another dose at this time, regardless of pregnancy status.

Where can I get the maternal RSV vaccine?

The vaccine is available through prenatal care providers, pharmacies, and public health clinics. Individuals should consult their healthcare provider for availability and scheduling.