Maternal RSV vaccination reduced infant hospitalizations

Maternal respiratory syncytial virus vaccination reduced infant hospital admission through 6 months.
*Prospective test-negative case-control study; Level 3 (OCEBM).

Citation

O’Hagan S, Cunningham S, Drysdale SB, et al. Lancet Child & Adolescent Health. 2026. doi:10.1016/S2352-4642(26)00134-3

Background

Respiratory syncytial virus is a leading cause of infant hospital admission for breathing illness. The United Kingdom introduced routine maternal vaccination in 2024; this study assessed real-world protection once the program was established.

Patients

Infants aged 6 months or younger admitted to 37 United Kingdom hospitals with acute lower respiratory tract infection and tested for respiratory syncytial virus. Primary analysis excluded infants born before 28 weeks’ gestation and those who received postnatal monoclonal antibody prevention.

Intervention

Maternal bivalent prefusion F respiratory syncytial virus vaccine during pregnancy, offered from 28 weeks’ gestation.

Control

No maternal respiratory syncytial virus vaccination before delivery.

Outcome

Hospital admission with respiratory syncytial virus-associated lower respiratory tract infection.

Follow-up Period

Until hospital discharge or inpatient death; effectiveness assessed to infant age 6 months.

Results

Primary analysis included 694 infants: 429 tested positive and 265 tested negative for respiratory syncytial virus. No inpatient deaths occurred.

Population or analysis Hospitalization prevention
Maternal vaccination, infants up to 6 months (primary) 61% effective (95% CI, 38–75)
Maternal vaccination, infants up to 3 months 76% effective (95% CI, 54–87)
Maternal vaccination more than 14 days before delivery 61% effective (95% CI, 39–76)
Overall United Kingdom prevention program 61% effective (95% CI, 39–75)

CI = confidence interval.

Analyses were adjusted for hospital site, month, gestational age, socioeconomic status, infant age, and breastfeeding. The control was not an alternative active prevention strategy. Among infected hospitalized infants, vaccinated mothers’ infants had the same median stay as unvaccinated mothers’ infants: 3 days.

Limitations

Observational design leaves possible remaining confounding. Results apply to hospitalized infants and not milder illness. Primary analysis excluded some high-risk infants receiving monoclonal antibody prevention. Protection beyond 6 months and effects on intensive care were not well assessed. The small statistical reduction in hospital stay was unlikely to be meaningful to families.

Funding

Mainly public/nonprofit funders; one author reported industry relationships.

Clinical Application

Offer maternal respiratory syncytial virus vaccination in pregnancy; evidence supports reduced infant hospitalization, especially in the first 3 months.