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

To determine the impact in other cities with different demographic profiles we used the inferred parameters from our linelist analysis to parameterise our transmission model for projections to other cities. We chose these to compare projections for a city with a high proportion of elderly individuals (Milan, Italy); a moderate-aged population (Birmingham, United Kingdom); and a city in a low-income country with a high proportion of young individuals (Bulawayo, Zimbabwe). For this analysis, we compared an outbreak of COVID-19, for which the burden and transmission is concentrated in relatively-older individuals, with an outbreak of pandemic influenza, for which the burden and transmission is concentrated in relatively-younger individuals. We assumed that immunity to influenza builds up over a person's lifetime, such that an individual's susceptibility to influenza infection plateaus at roughly age 35, and assumed that the severity of influenza infection is highest in the elderly and in children under 10 years old 7 .