Real-World Evidence of Factors Associated with Respiratory Syncytial Virus Mortality in Brazilian Children Under 5 Years, 2024

Abstract

To investigate the clinical, demographic, and healthcare factors associated with death from Respiratory Syncytial Virus (RSV) in children under 5 years of age in Brazil during 2024. Retrospective cohort study using real-world data (SIVEP-Gripe), following the RECORD protocol. A cohort of 24,022 confirmed cases was analyzed. Multivariate logistic regression was used to estimate Adjusted Odds Ratios (aOR), accompanied by sensitivity analysis (E-value) and predictive accuracy (ROC Curve). Hospital lethality was 1.02%. In the multivariate analysis, age was not an independent predictor of death (p = 0.951). The main factors associated with mortality were invasive ventilatory support (aOR 8.08; 95%CI 5.28–12.38; E-value 15.64), Down Syndrome (aOR 3.21; 95%CI 1.54–6.71), Heart Disease (aOR 2.57; 95%CI 1.42–4.66), and co-infection with 3 or more viruses (aOR 2.36; 95%CI 1.16–4.79). The presence of cough showed a protective effect (aOR 0.68; p = 0.029). The model showed excellent discriminatory capacity (AUC-ROC: 0.814). RSV mortality in hospitalized children in Brazil is driven by healthcare severity and specific comorbidities, regardless of chronological age. Immunization strategies and intensive support should prioritize biologically highly vulnerable groups, such as children with Down Syndrome and heart disease. Respiratory syncytial virus (RSV) is the leading cause of pediatric hospitalizations globally. Chronological age, particularly under six months, is traditionally considered the most significant risk factor for severe disease. Respiratory syncytial virus (RSV) is the leading cause of pediatric hospitalizations globally. Chronological age, particularly under six months, is traditionally considered the most significant risk factor for severe disease. In a massive real-world cohort of over 24,000 cases, chronological age was not an independent predictor of death among hospitalized children after adjusting for clinical severity. Biological vulnerabilities, specifically Down syndrome (aOR 3.21) and congenital heart disease (aOR 2.57), are the primary drivers of mortality. The absence of cough at admission serves as a potential clinical marker for respiratory exhaustion and a higher risk of death. In a massive real-world cohort of over 24,000 cases, chronological age was not an independent predictor of death among hospitalized children after adjusting for clinical severity. Biological vulnerabilities, specifically Down syndrome (aOR 3.21) and congenital heart disease (aOR 2.57), are the primary drivers of mortality. The absence of cough at admission serves as a potential clinical marker for respiratory exhaustion and a higher risk of death.