Analysis of incidence, mortality and lethality by COVID-19 in the States of Pará and Rio Grande do Sul, Brazil: epidemiological aspects of evolution 2020-2022

Abstract

Introduction: COVID-19 unfolded differently in Pará and Rio Grande do Sul, Brazil, owing to distinct socioeconomic contexts. From 2020 to 2022, both states implemented diverse measures against the virus SARS-CoV-2, including vaccination and variant monitoring, tailored to their specific challenges. Understanding regional impacts on COVID-19 indicators is crucial for designing effective control strategies. Objective: to analyze the incidence, mortality, and lethality of COVID-19 in Pará and Rio Grande do Sul and the trends of these indicators from 2020 to 2022. Methods: ecological study with time series from public and official data available in the Health Secretariat of Pará and Rio Grande do Sul, including all cases and deaths by COVID-19 from February 2020 to December 2022. Lethality, mortality, and incidence rates were calculated. Prais-Winsten regression analysis was used, and trends were classified as stationary, increasing, or decreasing. Significant differences were considered when the p-value is <0.05. Results: when examining the lethality rates between the states of Para and Rio Grande do Sul, an observable trend emerged during the analyzed period. It became evident that the total lethality rate consistently remained higher in Para. Noteworthy peaks in lethality were mainly observed during the months of April 2020, May 2020, and March 2021. The incidence rates showed increasing trends during 2020, both in Pará with a daily percentage change (DPC) of 1.69% (p <0.05) and in Rio Grande do Sul with a DPC of 1.70% (p<0.05). In 2021, the incidence was decreasing (p <0.05) in both states, with a DPC of 0.60% in Pará and 0.64% in Rio Grande do Sul and continued this trend in Pará in 2022 (DPC of -0.50% p <0.05), becoming stationary in Rio Grande do Sul, with a non-significant p-value (p> 0.05). Conclusion: the positive impact of the vaccination program is reflected in the evolution of the pandemic. During the study period Rio Grande do Sul and Para exhibited a stationary incidence trend, emphasizing the need for continued monitoring of cases and morbidity across various age and demographic groups.