Demographic science aids in understanding the spread and fatality rates of COVID-19

Jennifer Beam Dowd; Valentina Rotondi; Liliana Adriano; David M Brazel; Per Block; Xuejie Ding; Yan Liu; Melinda C Mills

The rapid spread of COVID-19 has revealed the need to understand how population dynamics interact with pandemics now and in the future. Population ageing is currently more pronounced in wealthier countries, which mercifully may lessen the impact of this pandemic on poorer countries with weaker health systems but younger age structures. It is plausible that poor general health status and coinfections such as tuberculosis may still increase the danger of COVID-19 among younger cases in these countries. Thus far, the lower than expected number of cases detected in Africa (despite extensive trade and travel links with China), suggests that the young age structure of the continent may be protective of severe and thus detectable cases, or it may be undetected. Beyond age structure, there are large sex differences in mortality that need to be understood -with men at higher risk -some of which may be accounted for by the stark differences in smoking rates by sex in Asia. Distributions of underlying comorbidities such as diabetes, hypertension and COPD will likewise refine risk estimates. Until these more nuanced data are available, the concentration of mortality risk in the oldest old ages remains one of the best tools we have to predict the burden of critical cases and thus more precise planning of availability of hospital beds, staff and other resources.