Serial interval and daily R_t estimates. (A) Simulated serial intervals based on the mean = 3.96 days and SD = 4.75 days estimated by Du et al. [17]. For the simulations, used to assess uncertainties in the estimates, we assumed a minimum mean = 3.53 and a maximum mean = 4.39 days, and a minimum SD = 4.46 and maximum SD = 5.07 days, which were based on the 95% credible intervals of the distribution estimated by Du et al. [17]. Each color line indicates a realization. For the simulations in the panel, we assumed a SD of 0.2 for the mean and variance, and we observed no major difference when increasing the SD to 1. (B) Daily R_t intervals, the horizontal dashed black line is the threshold when R_t = 1, whilevertical lines indicate the start of the COVID-19 suppression phases I and II described in Table 1.