Impact and Effectiveness of ABRYSVO® Vaccination During Pregnancy

This study will be conducted in collaboration with a research network of independent hospital sites to evaluate the vaccine effectiveness (VE) and impact of ABRYSVO vaccination during pregnancy in a real-world population over multiple seasons, which began in 2024 across Argentina and beginning in 2025 in Uruguay. We will use three retrospective design approaches in this study: (i) a test negative design (TND) to evaluate real-world VE of maternal ABRYSVO against RSV-associated outcomes in infants; (ii) a descriptive cohort design to evaluate the clinical evolution of infants hospitalized with RSV-positive lower respiratory tract disease (LRTD); and (iii) an ecologic before-and-after design to evaluate the impact of ABRYSVO vaccination during pregnancy on infant RSV-associated and all-cause respiratory outcomes.