Outbreak analysis with a logistic growth model shows COVID-19 suppression dynamics in China

Yi Zou; Stephen Pan; Peng Zhao; Lei Han; Xiaoxiang Wang; Johannes Knops; Wopke van der Werf; Lia Hemerik

The relative rate of increase in the number of cases at the time of the peak rate was rather 173 consistent among provinces, with an average of 0.11 cases/case/day for Hubei and 0.12 174 cases/case/day for the rest of China (range: 0.08 to 0.15). Between suppression 175 implementation and the peak number of reported cases, the number of active cases in Hubei 176 increased by a factor 39, while in other provinces it increased by a factor of 9.5 with 177 considerable variation between provinces (range: 6.2 in Hainan and Chongqing to 20.4 in 178 Heilongjiang). If a 6-day reporting delay is accounted for in the estimate of the factor increase 179 from the start of measures to the peak, then this multiplication factor is diminished to a value 180 of 9.5 for Hubei and an average of 2.6 for the other provinces. The daily death rate of the 181 active sick people was 0.34 percent per day for Hubei, much higher than in other provinces 182 (on average 0.05 percent per day, ranging between 0 in Jiangsu Province (see also Sun, Qiu 183 (25)) and 0.18 percent per day in Hainan Province, Appendix 3), which indicates that on the 184 faster than the rate of decline during the tapering out of the epidemic (Appendix A1). Thus, 210 the logistic underestimates both the early relative growth rate and the increase of the number 211 of sick people from the start of measures till the peak for the Chinese data (Appendix A1). 212