The ongoing coronavirus disease 2019 (COVID-19) pandemic poses a severe threat to publichealth worldwide. We combine data on demography, contact patterns, disease severity,and health care capacity and quality to understand its impact and inform strategies for its control.Younger populations in lower-income countries may reduce overall risk, but limited healthsystem capacity coupled with closer intergenerational contact largely negates this benefit.Mitigation strategies that slow but do not interrupt transmission will still lead to COVID-19epidemics rapidly overwhelming health systems,with substantial excess deaths in lower-incomecountries resulting from the poorer health care available. Of countries that have undertakensuppression to date, lower-income countrieshave acted earlier. However, this will need tobe maintained or triggered more frequently in these settings to keep below available healthcapacity, with associated detrimental consequences for the wider health, well-being, andeconomies of these countries.