The worldwide outbreak of the novel coronavirus (SARS-Cov-2) pneumonia remains a major public health concern. We thank Sharifi et al.’s comments to our recent study (Zhuang et al., 2020). In that paper we adopted the similar method as Imai's (Imai et al., 2020), which was used to estimate the number of COVID-19 cases in the early stages of the COVID-19 outbreak in Wuhan, Hubei, China. The model provided a rough range estimation about the epidemic size and has been recognized by peers as a valid method in the early stage of an epidemic (Kucharski et al., 2020; Boldog et al., 2020; Ng et al., 2020).