Maternal RSV Vaccine Shows Strong Protection For Infant Hospitalization
A maternal RSVpreF vaccine is 82% effective at preventing infant RSV hospitalization in the first three months of life, supporting its integration into routine prenatal care.
Maternal RSVpreF vaccination demonstrates high protection against infant RSV-associated hospitalization, with 82% effectiveness for infants up to 3 months and 78% for those up to 6 months when administered at least 14 days before delivery. This evidence arrives as RSV continues to cause severe illness in infants and health authorities seek effective antenatal strategies.
Evidence base and methodology
The conclusions are drawn from a systematic review of 7 studies covering 7112 infants, using rigorous meta-analytic methods to calculate effectiveness. The research team searched PubMed, Scopus, and Europe PMC from January 1, 2020, through January 30, 2026, initially identifying 1144 studies.
Of the 7112 infants in the final analysis, 2684 were born to vaccinated mothers. Data were collected from January 2024 through April 2025 in Argentina, the United Kingdom, and the United States. Vaccine effectiveness was calculated as (1-odds ratio) × 100% using random-effects models, specifically the Hartung-Knapp adjustment and the Sidik-Jonkman estimator.
The pooled results showed strong protection, though effectiveness varied slightly based on the infant's age and the timing of maternal vaccination.
| Infant Age Range | Vaccine Effectiveness (when given ≥14 days before delivery) | 95% Confidence Interval |
|---|---|---|
| 0 to 3 months | 82% | 81% to 82% |
| 0 to 6 months | 78% | 70% to 84% |
When the analysis included mothers vaccinated at any time during pregnancy, the effectiveness from birth to 6 months dropped to 68%. Joshua Fitch noted the core finding, stating: "Maternal RSVpreF vaccination was 82% effective against infant RSV-associated LRTI hospitalization from birth to 3 months." Neither the decline with infant age nor the difference by vaccination timing was statistically significant.
Clinical implications for practice
The investigators concluded that the findings support incorporating RSVpreF into routine antenatal immunization programs. The CDC recommends a single dose during 32 through 36 weeks' gestation for seasonal administration to protect infants after birth.
The sustained protection through six months is notable. Maternal-derived RSV F-specific IgG has an estimated half-life of approximately 38 days in infants, yet effectiveness was maintained. This supports the vaccine's role in shielding newborns during their most vulnerable early months.
The overall risk of bias in the reviewed studies was rated moderate to serious, with three retrospective studies judged at serious risk of confounding. Data were insufficient to analyze emergency department visits, intensive care unit admissions, or death; none of the studies reported mortality. Effectiveness in preterm infants could not be assessed.
Four Argentine studies in the analysis covered overlapping periods in 2024, but the maximum potential participant overlap was estimated at a minimal 2.7%. All but one study captured the first RSV season after program launch, meaning few infants older than three months were likely represented.
The authors called for further research in infants at higher risk of severe disease, against more severe outcomes, and with vaccination in the late second trimester. The systematic review and meta-analysis was published in JAMA Pediatrics in 2026 by Batool R, Wang R, Obeid H, and colleagues. The path forward centers on the incorporation of RSVpreF into routine antenatal immunization programs.
