COVID-19 Mortality and Temporal Trends in a Mid-Sized Southern Brazilian City (2020-2023): A Population-Based Retrospective Study.

BACKGROUND AND AIMS: The COVID-19 pandemic has significantly impacted global mortality, with marked variations according to demographic and temporal factors. This study aimed to analyze COVID-19 mortality trends and associated demographic factors in Chapecó, Southern Brazil, between 2020 and 2023.

METHODS

This population-based retrospective observational study included all confirmed COVID-19 cases and related deaths recorded from March 2020 to March 2023. Data were obtained from the Municipal Epidemiological Surveillance Service. Demographic variables (age, sex, and year of occurrence) were analyzed. Mortality was evaluated using multivariable logistic regression models, incorporating variables selected based on epidemiological relevance. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated. Statistical significance was set at α = 0.05.

RESULTS

A total of 84,814 COVID-19 cases and 861 deaths were recorded (case fatality rate: 1.02%). Mortality was higher among males (61.1%) and increased significantly with age, with a 10.2% higher odds of death per additional year of age. Compared with 2020, mortality risk was higher in 2021 (OR = 2.07; 95% CI: 1.72-2.50) and significantly lower in 2022 (OR = 0.15; 95% CI: 0.11-0.21). Peaks in case incidence during 2022 were not accompanied by proportional increases in mortality.

CONCLUSION

COVID-19 mortality in Chapecó was strongly associated with age and male sex. The substantial reduction in mortality after 2021 highlights the impact of vaccination and improved public health measures in mitigating pandemic outcomes.