An international research team has conducted the first comprehensive global-to-local assessment of the direct health burden of COVID-19, spanning 920 locations worldwide. Utilizing the Global Burden of Disease (GBD) 2021 analytical framework, the study examined data from 2020 and 2021 across five spatial levels—global, international regional, national, subnational, and local. It quantified the pandemic's impact through core health metrics: incidence (new cases), prevalence (existing cases), mortality (deaths), and disability-adjusted life years (DALYs), which combine years lived with disability (YLDs) and years of life lost (YLLs) due to premature death.
The findings reveal pronounced and widespread disparities in COVID-19 outcomes across and within areas. "Our analysis clearly suggests that the pandemic did not affect all communities equally," said Dan Shan, first and corresponding author of the study. "Some locations experienced remarkably higher rates of infection, mortality, and healthy life years lost. These were often locations with limited health and socioeconomic resources—something we should address in future responses."
Notably, the study documented disparities not only between countries but also within them. While more advantaged populations often experienced better outcomes, disadvantaged and marginalized groups—such as those in rural, low-income, or underserved areas—frequently bore a heavier burden. These patterns underscore the critical role of social and structural determinants in shaping pandemic outcomes. However, the heterogeneity of findings across the 204 countries and territories analyzed points to the importance of high-resolution, location-specific data. "Relying solely on national or regional averages may obscure severe local outbreaks and vulnerabilities," Shan explained. "By drilling down to finer geographic levels, we identified communities in crisis whose suffering would otherwise have remained hidden."
The authors emphasize that these results carry major implications for public health policy. Inadequate granularity in surveillance data could cause at-risk populations to be overlooked, weakening both short-term responses and long-term preparedness. The data presented by this study offers an essential foundation for designing targeted, equity-oriented interventions and for prioritizing high-burden communities in future health emergencies. Importantly, the study's insights may also help identify populations that could be more vulnerable to long-term post-COVID conditions, such as long COVID, particularly in areas with disproportionately high YLD burdens during the early phases of the pandemic. "We hope our findings will support the development of more equitable and data-driven health policies—so that no area, no matter how small or under-resourced, is left behind in the next public health crisis," Shan concluded. Overall, the study provides timely and actionable evidence to strengthen health systems and promote fairness in pandemic preparedness and response.
