Maternal RSV vaccination reduces infant hospitalizations

Maternal respiratory syncytial virus prefusion F vaccination was linked to about two-thirds fewer infant hospitalizations for respiratory syncytial virus in the first 90 days of life.
*Retrospective test-negative case-control study; Level 3b (OCEBM).

Citation

Rick AM, Deese J, Kerr JE, et al. Maternal respiratory syncytial virus prefusion F vaccination and acute respiratory illness in infants. JAMA Network Open. 2026;9(6):e2616773. doi:10.1001/jamanetworkopen.2026.16773

Background

Respiratory syncytial virus is a leading cause of infant hospitalization, especially in early infancy. A maternal vaccine was licensed in 2023, but early real-world effectiveness data have been limited.

Patients

Infants aged 0 to 90 days hospitalized with acute respiratory illness in one western Pennsylvania health system during the 2023-2024 and 2024-2025 seasons (n=274). Excluded: infants who received a preventive antibody for respiratory syncytial virus, infants whose mothers received a different respiratory syncytial virus vaccine, and infants with unverified maternal vaccination status.

Intervention

Maternal respiratory syncytial virus prefusion F vaccination at 32 to 36 weeks of pregnancy and at least 14 days before delivery.

Control

Infants hospitalized with acute respiratory illness who tested negative for respiratory syncytial virus.

Outcome

Hospitalization with respiratory syncytial virus–associated acute respiratory illness (primary) and hospitalization with respiratory syncytial virus–associated lower respiratory tract disease (secondary).

Follow-up Period

Birth through 90 days of age (exploratory: 0 to 30 days).

Results

Outcome Adjusted odds ratio (95% CI) Vaccine effectiveness (95% CI)
Respiratory syncytial virus–associated acute respiratory illness hospitalization, 0-90 days (primary) 0.32 (0.15 to 0.67) 67.6% (33.2% to 85.4%)
Respiratory syncytial virus–associated lower respiratory tract disease hospitalization, 0-90 days 0.31 (0.12 to 0.75) 69.0% (25.5% to 88.0%)
Respiratory syncytial virus–associated acute respiratory illness hospitalization, 0-30 days 0.26 (0.07 to 0.75) 74.2% (25.4% to 93.0%)

Limitations

Observational design leaves possible residual confounding. Single health system limits generalizability. Few vaccinated case infants led to wide confidence intervals. Findings address prevention of hospitalization, not mild outpatient illness.

Funding

Pfizer; also supported by National Institutes of Health informatics grant.

Clinical Application

For eligible pregnancies, offer maternal respiratory syncytial virus vaccination to reduce early-infant respiratory syncytial virus hospitalizations; results support current recommendations but do not address non-hospitalized infection.