Maternal RSVpreF vaccination was 78–82% effective against infant RSV admission after rollout

Design

Systematic review and meta-analysis of non-randomised post-implementation studies

Population

7 studies, 7,112 infants (2,684 born to vaccinated mothers)

Primary outcome

RSV-associated lower respiratory tract infection admission

Effect

Effectiveness 82% (81% to 82%) to 3 months; 78% (70% to 84%) to 6 months

A systematic review pooled seven non-randomised post-implementation studies from Argentina, the UK and the US, covering 7,112 infants, 2,684 born to vaccinated mothers, from January 2024 to April 2025.

When mothers were vaccinated at least 14 days before delivery, vaccine effectiveness against RSV lower respiratory tract infection admission was 82% from birth to 3 months (3 studies, no heterogeneity) and 78% from birth to 6 months (6 studies, low heterogeneity). Data were too sparse to pool emergency visits, intensive care admissions or deaths.

Real-world protection matched or exceeded the pivotal trial. The practical detail that matters is timing: protection depends on vaccination at least 2 weeks before birth. In India RSVpreF is not part of the national programme and its availability is not established here; the alternative for the infant, where available, is a long-acting monoclonal antibody.

• Discuss maternal RSV vaccination during the recommended gestational window where it is available
• Vaccinate at least 14 days before expected delivery
• Record maternal vaccination in the infant's notes
• Infants born within 14 days of vaccination need other protection where available
• Do not give both maternal vaccine and infant monoclonal routinely

Why it matters

It confirms the trial result holds in routine use, which is what programmes need before adopting it.

Don't overread it

These are observational test-negative and cohort studies from high- and middle-income settings, not trials, and severe outcomes were not pooled.

The statistics, in plain English

Vaccine effectiveness is calculated as one minus the odds ratio: an OR of 0.18 gives 82%. The very narrow interval to 3 months (81% to 82%) comes from large, consistent studies. Observational designs can be biased if vaccinated mothers differ from unvaccinated ones, but the agreement with the randomised trial is reassuring.

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