Mortality from Acute Bronchiolitis in Infants under 1 Year of Age between 2014 and 2024 in Brazil: An Ecological Time Series Study

Abstract

ABSTRACT

Introduction: Acute bronchiolitis is the leading cause of hospitalization and death due to respiratory infection in children under one year of age. Recently, the epidemiological profile of the disease has been drastically altered by the "immunity debt" phenomenon following the COVID-19 pandemic, making the monitoring of mortality indicators in the country essential.

Objectives: To analyze the magnitude and trend of mortality from acute bronchiolitis in children under one year of age in Brazil (2014-2024), characterizing temporal dynamics and sociodemographic profiles to support public policies and the improvement of pediatric care.

Methodology: A quantitative cross-sectional study based on secondary data from the Department of Informatics of the Unified Health System (Mortality Information System and Live Birth Information System). Deaths (ICD-10: J21) were analyzed by year, region, age group, sex, and ethnicity. Specific mortality rates and proportional mortality were calculated and systematized using electronic spreadsheets.

Results: A total of 2,855 deaths were recorded. The trajectory was upward until 2019 (244), followed by a decline in 2020 (68). The final biennium showed a sharp surge, peaking in 2023 (577 deaths; 20.2%) and remaining high in 2024 (537). The national rate in 2023 (0.227/1,000 live births) was four times higher than in 2014, a fact associated with the post-pandemic "immunity debt." The Southeast region held the highest absolute burden (46.5%), while the Northeast (0.296) and Midwest (0.261) presented the highest epidemiological risks in 2023. Mortality was concentrated among infants aged 28-364 days (96.7%), males (57.7%), and White (46.0%) and Pardo (42.1%) ethnicities. Proportional mortality reached 1.80% in 2023, consolidating the pathology as a critical cause of death.

Conclusion: Bronchiolitis has consolidated as a growing threat to infants. The worsening indicators highlight healthcare vulnerabilities and regional inequalities. It is imperative to advance the decentralization of intensive care beds and the implementation of new preventive technologies, such as long-acting monoclonal antibodies, aiming to reduce preventable infant mortality in the country.