- Design
- Systematic review and meta-analysis of 7 non-randomised post-implementation studies
- Population
- 7,112 infants (2,684 born to RSVpreF-vaccinated mothers), Argentina, UK, US
- Primary outcome
- RSV-associated lower-respiratory-tract hospitalisation
- Effect
- Effectiveness 82% (0–3 months) and 78% (0–6 months) with vaccination ≥14 days before delivery
RSVpreF, the bivalent RSV vaccine given in pregnancy, protected infants in its pivotal trial; this meta-analysis asks whether that holds in practice. It pooled seven post-implementation studies (7,112 infants, 2,684 born to vaccinated mothers) from Argentina, the UK and the US.
When the mother was vaccinated at least 14 days before delivery, effectiveness against RSV lower-respiratory-tract hospitalisation was 82% (95% CI 81–82) in the first three months of life and 78% (70–84) through six months, with little heterogeneity. These are the months when RSV is most dangerous to a baby.
The finding supports putting RSVpreF into routine antenatal immunisation, maternal vaccination timed to give at least two weeks before birth. In India the vaccine is not yet part of routine antenatal care and access and cost are unresolved, but the evidence base for maternal RSV immunisation is now real-world, not just trial-based.
- Maternal RSVpreF was about 80% effective against infant RSV hospitalisation in the first months of life.
- Protection required vaccination at least 14 days before delivery.
- Effectiveness was consistent across countries, with little heterogeneity.
- The data support antenatal RSV vaccination where the vaccine is available.
Why it matters
It moves maternal RSV vaccination from trial efficacy to confirmed real-world protection, strengthening the case for antenatal programmes.
Don't overread it
These are non-randomised post-implementation studies; the effectiveness estimate is consistent but could be influenced by who chooses vaccination.
The statistics, in plain English
An effectiveness of 82% means roughly four in five RSV hospitalisations prevented; the very tight confidence interval and near-zero heterogeneity show the studies agree, though non-randomised data can still carry selection effects.
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