Maternal RSVpreF Immunisation Against Infant RSV Hospitalisation: Nationwide Population-Based Effectiveness and...

Area of Science:

• Immunology
• Pediatrics
• Public Health

Background:

• Limited real-world data exists on the effectiveness of the maternal respiratory syncytial virus prefusion F protein (RSVpreF) vaccine.
• Assessing vaccine effectiveness and durability in infants is crucial for public health strategies.

Purpose of the Study:

• To estimate the real-world effectiveness and durability of the maternal RSVpreF vaccine against RSV-associated hospitalizations in infants.
• To evaluate the vaccine's impact on severe respiratory outcomes.

Main Methods:

• Nationwide cohort study in France emulating a target trial using French National Health Data System.
• Infants born to vaccinated mothers were matched 1:1 with unimmunized infants.
• Inverse probability weighting and Cox models were used to estimate hazard ratios and vaccine effectiveness.

Main Results:

• Maternal RSVpreF immunization showed 50% effectiveness (95% CI 45-55) against RSV-LRTI hospitalization.
• Protection was highest in the first 14 days of life (66%) and decreased over time.
• Significant reductions were observed for severe outcomes like ICU admission (51%), oxygen therapy (54%), and ventilatory support (53%).

Conclusions:

• Maternal RSVpreF vaccination is effective in reducing RSV-associated hospitalizations in infants.
• The vaccine provides substantial early-life protection, though durability wanes over time.
• These findings support the use of maternal RSVpreF vaccination for infant protection against RSV disease.