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Bivalent Prefusion F Vaccination in Pregnancy and Respiratory Syncytial Virus Hospitalisation in Infants: Results of a Prospective, Multi-Centre, Test-Negative Study
17 Pages Posted: 25 Mar 2025
More...Abstract
Background: Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory infections (ALRI) in infants less than 6 months old globally. A maternal bivalent RSV prefusion F (RSVpreF) vaccine was introduced to the United Kingdom in late summer 2024, incorporating an initial catch-up campaign, with all pregnant women at a gestation of 28 weeks or more eligible for vaccination.
Methods: We conducted a prospective, multi-centre, test-negative study to analyse the effectiveness of maternal RSVpreF vaccination against hospitalisation for RSV-associated ALRI in infants. Included patients were infants born after August 12, 2024 (Scotland) and September 1, 2024 (England), who therefore had mothers eligible for maternal vaccination, and who were hospitalised with ALRI to January 20, 2025. Primary vaccine effectiveness (VE) of maternal RSVpreF vaccination against RSV-associated hospitalisation was calculated with the use of an un-matched conditional logistic regression stratified by site and calendar month of attendance with age, prematurity, and sex as co-factors.
Findings: The study included 391 RSV-positive cases (median age, 1.6 months, interquartile range 0.9-2.3) and 146 RSV-negative controls (median age, 1.4 months, interquartile range 0.8-2.0). The mothers of 73 RSV-positive case patients (18.7%) and 60 RSV-negative control patients (41.1%) had received RSVpreF vaccine prior to delivery. The adjusted effectiveness of maternal RSVpreF vaccination for preventing infant hospitalisation was 72.4% (95% confidence interval [CI] 47.8 to 85.4) for infants whose mothers were vaccinated more than 14 days before delivery, and 57.7% (95% CI 28.2 to 75.1) for infants whose mothers were vaccinated at any time before delivery.
Interpretation: In the real-world setting of a catch-up campaign, maternal vaccination was effective and equivalent to trial settings in reducing the risk of hospitalisation in infants with RSV-associated ALRI.
Keywords: Respiratory syncytial virus, maternal vaccination, vaccine effectiveness
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