Characterization of outpatient respiratory syncytial virus infection in children under 5 years of age in a tertiary-level hospital.

Introduction. Respiratory syncytial virus (RSV) is a leading cause of acute respiratory infections. This study aimed to characterize outpatient RSV cases in children under 5 years of age who attended a public pediatric hospital. Population and methods. Cross-sectional study between 2022 and 2024. We analyzed 102 ambulatory cases of acute respiratory infection due to RSV diagnosed in the Ambulatory Monitoring Unit. Results: The median age was 16.4 months; 70% were younger than 24 months, and 54.9% were male. Most of the patients belonged to the middle class, and 62.5% of the mothers had a secondary education or higher; 88.7% were born at term, 54% by cesarean section, and 43.2% were exclusively breastfed until six months; 19.6% had some comorbidity. The most common manifestations were cough (99%), fever (86%), rhinorrhea (84%), and respiratory distress (32%). The primary diagnoses were bronchiolitis or obstructive bronchial syndrome (50.9%) and influenza-like illness (30.4%). Antibiotics were administered to 21.6% of the patients. Of the working caregivers, 62.5% had to be absent from work, with a median absence of 1.5 days. Conclusion. In patients attended on an outpatient basis, RSV presented seasonally, affecting mainly healthy children aged 13-24 months, with bronchiolitis being the most common diagnosis.