Age-dependent effects in the transmission and control of COVID-19 epidemics

Nicholas G Davies; Petra Klepac; Yang Liu; Kiesha Prem; Mark Jit; Rosalind M Eggo

Strong age dependence in the fraction of COVID-19 infections that become clinical cases has implications for the projected global burden. Simulating COVID-19 outbreaks in 146 capital cities, we found that the total expected number of clinical cases in an unmitigated epidemic varied between countries depending on the median age of the population, which is a proxy for the age structure of the population. The total clinical attack rate was higher, and the peak height of the epidemic was greater, in older populations ( Fig 4a ) . By contrast, the number and peak of subclinical infections was lower in older populations ( Fig 4b ) . The mean estimated basic reproduction number, R 0 , was higher in cities with a lower median age ( Fig 4c ) , because of the greater proportion of children and the higher number of contacts made by children compared to adults. We applied the same age-dependent clinical fraction to all 10 . CC-BY 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.