Fig. 1
From: Optimal timing and effectiveness of COVID-19 outbreak responses in China: a modelling study
State transition diagram for the Wuhan model. States include Susceptible (S), Exposed (E), Infected and asymptomatic (IA), Infected and symptomatic (IS), and Recovered (R). Each day, individuals may stay in their current health state, progress to another possible health state, leave Wuhan (outbound travel), or arrive in Wuhan (inbound travel). We assumed that individuals arriving in Wuhan were all susceptible. Given the short time horizon, we only modeled death due to symptomatic COVID-19 infections. All compartments were stratified by age