Factors associated with severity and fatality of COVID-19 in Brazilian children and adolescents (2020-2023): a population-based study.

COVID-19 pandemic posed significant health challenges worldwide, with substantial impact on pediatric populations. In Brazil, hospitalizations and deaths among children and adolescents have continued throughout the pandemic despite beginning of vaccination. The objective of this study was to analyze sociodemographic background, presentation, and clinical outcomes among hospitalized Brazilian individuals under 20 years with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, analyzing risk factors for severity and death according to age group. Consisted of a population-based cross-sectional study using secondary data from children and adolescents (<20 years) hospitalized with COVID-19 in Brazil (March 2020-December 2023). Data from Influenza Epidemiological Surveillance Information System (SIVEP-Gripe) included sociodemographic, clinical, and vaccination information. Cox proportional hazards models assessed intensive care unit (ICU) admission, invasive mechanical ventilation (IMV), and fatality by age group; 30-day survival was estimated using Kaplan-Meier analysis. A total of 123 382 hospitalizations were recorded; children under five accounted for 56.2% of cases and 43.3% of deaths. Hospitalized adolescents (11-19 years) showed the most severe outcomes, with relatively higher ICU admission (30.9%), IMV use (11.8%), and fatality (6.5%), in addition to lower overall survival (48.3%). Across all age groups, being hospitalized in the North or Northeast and IMV were associated with the highest risk of death. Overall, only 10.4% of the study population had received at least one vaccine dose. Adolescents experienced a higher relative frequency of severe clinical outcomes and lowest survival, although, in absolute numbers, more children under 5 years of age were hospitalized and died. These findings underscore the urgency of expanding pediatric vaccine coverage as a public health priority in Brazil.