Abstract for: Investigating the effectiveness of reopening policies before vaccination during a pandemic

Lockdown policies were widely applied during the COVID-19 pandemic to control the spread of the virus before the availability of a vaccine, causing significant economic impact and social disruption. Early reopening is preferred, yet it introduces the risk of further outbreaks. So far, the effectiveness of reopening policies remains unclear. A system dynamics COVID-19 model, SEIHR(Q), was constructed by integrating infection prevention and control measures implemented in Wuhan into the classic SEIR epidemiological model. Simulation results showed that track-and-trace measures were of significance in affecting reopen risk. In Wuhan’s case, with comprehensive contact tracing implemented, there would have been almost no risk for reopening. With partial contact tracing, reopening would have led to a minor second wave of the epidemic. However, if only limited contact tracing had been implemented, a more severe second outbreak of the epidemic would have occurred, overwhelming the available medical resources. When the ability to implement a track-trace-quarantine policy is fixed, the epidemiological criteria need to be further taken into account. A matrix was developed to evaluate the effectiveness of the reopening policies, based on simulation results. The model simulation provides evidence-based decision support for safe reopening during an ongoing epidemic.