Are COVID-19 age-mortality curves for 2020 flatter in developing countries? Evidence from a cross-sectional observational study of population-level official death counts and excess deaths estimates

OBJECTIVES: Previous studies have found a pattern of flatter COVID-19 age-mortality curves among low-income and middle-income countries (LMICs) using only official COVID-19 death counts. This study examines this question by comparing the age gradient of COVID-19 mortality in a broad set of countries using both official COVID-19 death counts and excess mortality estimates for 2020. DESIGN: This observational study uses official COVID-19 death counts for 76 countries and excess death estimates for 42 countries. A standardised population analysis was conducted to assess the extent to which variation across countries in the age distribution of COVID-19 deaths was driven by variation in the population age distribution. SETTING AND PRIMARY OUTCOMES: Officially reported COVID-19 deaths and excess deaths for 2020 for all countries where such data were available in the COVerAGE database and the short-term mortality fluctuations harmonised data series, respectively. RESULTS: A higher share of pandemic-related deaths in 2020 occurred at younger ages in middle-income countries compared with high-income countries. People under age 65 years constituted on average (1) 10% of official deaths and 11 % of excess deaths in high-income countries, (2) 34% of official deaths and 33% of excess deaths in upper-middle-income countries, and (3) 54% of official deaths in LMICs. These contrasting profiles are due only in part to differences in population age structure. CONCLUSIONS: These findings are driven by some combination of variation in age patterns of infection rates and infection fatality rates. They indicate that COVID-19 is not just a danger to older people in developing countries, where a large share of victims are people of working age, who are caregivers and breadwinners for their families.