Changes in the Epidemiological Pattern of Dengue in Brazil Across the Pre-, During-, and Post-COVID-19 Periods: A Segmented Time Series Study (2016–2025)Changes in the Epidemiological Pattern of Dengue in Brazil Across the Pre-, During-, and Post-COVID-19

Abstract

Dengue is an arboviral disease of major public health importance, with a progressive increase in cases over recent decades, particularly in tropical countries. In Brazil, the epidemiological dynamics of dengue may have been influenced by the COVID-19 pandemic, potentially affecting disease notification, transmission patterns, and clinical severity. This study aimed to analyze the temporal trends of dengue incidence, hospitalization, and mortality in Brazil from 2016 to 2025, comparing the pre-pandemic, pandemic, and post-pandemic periods. An epidemiological time series study was conducted using secondary data obtained from the Brazilian Notifiable Diseases Information System (SINAN). Probable dengue cases, hospitalizations, and deaths were analyzed according to year of notification. The study period was divided into three phases: pre-pandemic (2016–2019), pandemic (2020–2022), and post-pandemic (2023–2025). Incidence and mortality rates per 100,000 inhabitants were calculated, as well as hospitalization proportion and case fatality rate. A total of 16,409,346 probable cases and 13,244 deaths were recorded during the study period. A decrease in reported cases was observed during the initial pandemic years, followed by a progressive increase, with a historical peak in 2024. Mortality and case fatality rates increased in the post-pandemic period, indicating a greater recent clinical impact of the disease. In conclusion, a shift in the epidemiological pattern of dengue was observed in Brazil after the COVID-19 pandemic, characterized by a marked increase in incidence and mortality. These findings highlight the need to strengthen surveillance and control measures to mitigate future epidemic outbreaks.