On the heterogeneity of infections, containment measures and the preliminary forecast of COVID-19 epidemic

As of May 1, 2020, there had been over three million of officially confirmed cases of novel coronavirus (COVID-19) infections reported worldwide. The pandemic originated from a severe acute respiratory syndrome coronavirus 2 (SARSCoV-2), a virus similar to severe acute respiratory syndrome (SARS). The dynamics of the pathogen incurred the incidence of the unidentified cases that were potentially substantial in magnitude. Unparalleled extensive measures, either in terms of medical quarantine or non-medical containment, were taken to deplete the growth of infected population and thereafter settle down the outbreak. We aimed to estimate the gap in sizes and peak dates between the confirmed and unconfirmed, and how containment measures impacted the dynamic trajectory of the COVID-19 in Japan. We performed simulations and desired to provide meaningful insight for the upcoming responses to the outbreak, for which much still remained to be unknown.