Efficacy of maternal immunization with Abrysvo in the prevention of acute viral bronchiolitis in infants

Abstract

Respiratory syncytial virus (RSV) is one of the leading causes of lower respiratory tract infections in infants and is strongly associated with acute viral bronchiolitis and pediatric hospitalizations worldwide. In this context, maternal immunization has emerged as a promising strategy to protect newborns during the first months of life. The aim of this study was to analyze the scientific evidence regarding the effectiveness of maternal immunization with the RSVpreF vaccine (Abrysvo) in preventing acute viral bronchiolitis and other RSV-associated lower respiratory tract infections in infants. This study consists of an integrative literature review conducted in the PubMed, SciELO, and ScienceDirect databases. Articles published between 2018 and 2025 in Portuguese, English, or Spanish addressing maternal RSV vaccination and prevention of respiratory infections in infants were included. After applying the inclusion and exclusion criteria and removing duplicates, 20 studies were selected for analysis. The results indicate that maternal vaccination with RSVpreF shows significant effectiveness in preventing RSV-associated respiratory infections during the first months of life and demonstrates efficient transplacental transfer of neutralizing antibodies to the newborn. Additionally, a reduction in the incidence of lower respiratory tract disease and a potential decrease in infant hospitalizations related to RSV were observed. Regarding safety, the studies indicate a favorable safety profile for vaccination during pregnancy, with mostly mild and transient adverse events. In conclusion, maternal RSV immunization represents an effective and safe strategy for preventing acute viral bronchiolitis in infants and may have an important impact on public health.