The Estimated Time-Varying Reproduction Numbers during the Ongoing Epidemic of the Coronavirus Disease 2019 (COVID-19) in China

Fu-Chang Hu; Fang-Yu Wen

Almost everyone was susceptible to the novel COVID-19 and this was one of the reasons why the COVID-19 epidemic occurred at many places and caused public panics in China and worldwide. In terms of population size, the depletions due to death or recovery might be negligible in China. And, there were no imported cases of COVID-19 in China. These features made the task of modeling this epidemic in China relatively easier. However, since the COVID-19 was new to human society, its diagnostic criteria, control measures, and medical cares were inevitably changing during the epidemic as the knowledge and experience about it were accumulated continuously. 2 We decided not to exclude the added clinically diagnosed cases of the Hubei Province during February 12−16, 2020 for the robustness of our epidemic analysis. In addition, many recoveries were probably not susceptible any more in the late phase of the epidemic. Thus, the result obtained in this study was merely a rough estimate of R0(t). Nevertheless, our findings (esp., Figure This study had several limitations because we relied on some assumptions to make a rapid analysis of this ongoing epidemic feasible. First, we assumed that all . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. However, as for the SARS epidemic in Singapore, the SI tended to be shorter after control measures were implemented. 13 In fact, the SI also depended on the amount of infecting dose, the level of host immunity, and the frequency of person-to-person contacts. Most of these limitations led our estimation of R0(t) into a more conservative context.