Residual burden of severe RSV disease in infants during the first season of maternal RSVpreF immunization in Argentina: A hospital-based, multicentre, retrospective cohort study
Year: 2026
Type: article
Study design: Observational Study
Abstract: BACKGROUND: Argentina pioneered the implementation of maternal immunization (MI) with RSVpreF to prevent RSV hospitalizations in infants. This study aims to assess the residual burden of RSV-related hospitalizations in infants under 12 months during Argentina's first season of MI. METHODS: This multicentre, retrospective cohort study utilized the RIMA network across five tertiary hospitals in the Metropolitan Area of Buenos Aires. We analysed RSV-related hospitalizations in infants <12 months old during the first post-MI season (2024) and compared them with historical data (2018-2023). The primary objective was to characterize the "protection gap" among hospitalized infants. FINDINGS: Overall, 10,860 infants aged <12 months were hospitalized with ALRTI during the study; 3967 (36.29%) were RSV-positive. During the first vaccination season, 91.73% (477/520) of RSV-hospitalized infants were born to unvaccinated mothers. The primary protection gap was temporal: 43.18% (133/308) of infants under 6 months hospitalized during 2024 were born before the vaccination campaign started. Severe RSV disease remained prevalent, with 131/148 infants (88.52%) requiring PICU admission. INTERPRETATIONS: While maternal immunization is a landmark intervention, a substantial residual burden of severe RSV remains in Argentina. This burden is driven by infants born outside the vaccination window and high-risk preterm cohorts. To achieve comprehensive protection, coordinated strategies, including the integration of long-acting monoclonal antibodies alongside maternal vaccines, are necessary to close existing equity and protection gaps. FUNDING: This work was supported by SANOFI and AstraZeneca (RSV00105).
Source: Vaccine
Authors: Julia Dvorkin, María Pico, Gonzalo Guiñazú, María Sol Crespi, Shona Lee, Rosario Merlino, Juliana Palau, Celeste Samaruga, Sofia Esposto, Micaela Pichinenda, Anastasia Regalado, Valeria Torre, Gabriela Sanluis Fenelli, María Fabiana Ossorio, Agustina Sbruzzi, Stella Maris Souto, Fernando Ferrero, Juan Ves Losada, Ana Graziano, María Nieves Ojeda, Silvana Lugo, Guadalupe Geli, Mónica Schpilberg, Alfredo Eymann, Julio Busaniche, Mauricio T. Caballero
Language: English
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $3,620
Award: G6172271585
OpenAlex ID: W7162783308