a, Age dependence in clinical fraction (severity) and susceptibility to infection on contact for COVID-19 and for the influenza-like scenarios (simplified, based on ref. 44) considered here. b, Age structure for the three exemplar cities. c, Age-specific clinical case rate for COVID-19 and influenza-like infections, assuming 50% infectiousness of subclinical infections. d, Daily incidence of clinical cases in exemplar cities for COVID-19 versus influenza-like infections. R0 is fixed at 2.4. The rows show the effect of varying the infectiousness of subclinical infections to be 0%, 50% or 100% as infectious as clinical cases while keeping R0 fixed. e, Change in peak timing and peak cases for the three cities, for either COVID-19 or influenza-like infections. f, Change in median COVID-19 peak timing and peak cases for the three cities, depending on the infectiousness of subclinical infections.