Trends and cross-country disparity in the burden of COVID-19 between 2020 and 2021: a systematic analysis for the Global Burden of Disease Study 2021

Background Coronavirus disease 2019 (COVID-19) has led to extensive repercussions on global health and economic systems. In this study, we aim to provide an analysis of global, national, and regional COVID-19 incidence, mortality, and disability-adjusted life years (DALYs) for the years of 2020 and 2021. Methods Data on COVID-19 incidence, DALYs, and mortality were derived from the Global Burden of Disease Study 2019. The data were carefully estimated and presented in both numerical values and age-standardized rates (ASRs) per 100,000 individuals, inclusive of 95% uncertainty intervals (UI). The study further stratified the COVID-19 burden by age, gender, sociodemographic index (SDI), and health system infrastructure. Additionally, the correlation between ASR and SDI was examined. Findings There were marked disparities in the COVID-19 burden across various countries and regions in 2020 and 2021. Globally, the number and ASR of incidence, DALYs and death showed an increasing trend from 2020 to 2021, particularly in regions with lower SDI and less robust healthcare systems. Men exhibited higher numbers and ASRs of DALYs and death. The elderly experienced higher DALYs and mortality, despite of having the lowest incidence rates. Furthermore, a significant negative correlation was observed between SDI and the ASRs of incidence, DALYs, and death across 21 regions and 204 countries. Conclusion This study highlights a pronounced escalation in the COVID-19 burden from 2020 to 2021, with the elderly, males, those in lower SDI and less developed healthcare systems regions being disproportionately affected. A comprehensive understanding of COVID-19 epidemiology is essential for devising strategies to mitigate the disease's impact.