Figure 2.

Estimates of R_t in Beijing, Shanghai, Shenzhen, and Wenzhou

(A) The daily number of symptom onsets in Beijing (411 cases), Shanghai (337 cases), Shenzhen (417 cases), and Wenzhou (504 cases), stratified by local cases (blue), imported cases from Wuhan or Hubei (red). The epidemic curves were estimated from cases reported on or before Feb 29, 2020. The daily number of symptom onsets observed or estimated from reported cases between Feb 29 and March 16, are shown, but not included in the analysis. Imported cases from overseas were reported in Beijing, Shanghai, and Shenzhen since March 1 (green). The date of symptom onset was available for 186 of 212 cases who were reported in Beijing on or before Feb 2, 2020, and for each case in Shenzhen and Wenzhou. The date of symptom onset was not available for the remaining 225 cases in Beijing, and all cases in Shanghai. Therefore, we estimated the date of onset for the 225 cases in Beijing and all cases in Shanghai based on their date of reporting and Beijing's distribution of the time between onset and reporting (which was estimated from the 186 cases reported by Feb 2, in Beijing). (B) The estimates of R_t by date of symptom onset on sliding weekly windows between late January, and Feb 19, 2020, for Beijing and Shanghai, and between mid-January, and Feb 25, 2020, for Shenzhen and Wenzhou (eg, the estimate on Feb 25 was for the week of Feb 22–28). We estimated R_t until Feb 19, because few cases reported in the week of Feb 22–28, and the estimation of the onset dates of these cases was not accurate. Dots show the posterior mean and bars show 95% credible intervals. R_t=instantaneous effective reproduction number.