Evolving Epidemiology and Impact of Non-pharmaceutical Interventions on the Outbreak of Coronavirus Disease 2019 in Wuhan, China

Chaolong Wang; Li Liu; Xingjie Hao; Huan Guo; Qi Wang; Jiao Huang; Na He; Hongjie Yu; Xihong Lin; An Pan; Sheng Wei; Tangchun Wu

Despite that the outbreak started in early December, no strong interventions were taken before January 20 when the human-to-human transmission was officially announced. The outbreak quickly spread from the urban areas to the suburban and rural areas. The attack rate in the healthcare workers was substantially higher between January 11 and February 1, indicating a high risk of nosocomial infections. This was probably due to lower awareness of protection before January 20, and later severe shortage of medical resources including designated wards and personal protective equipment in hospitals confronting overwhelmed patients. We compared our model prediction with published modeling studies using independent datasets. Based on early international exported cases, Wu et al. 9 estimated that 75,815 (95% CrI, 37,304 to 130,330) individuals had been infected in Greater Wuhan as of January 25, 2020. For comparison, we estimated the number to be 36,798 (95% CrI, 30,898 to 43,390) by the same day, including both ascertained and unascertained cases. The discrepancy was mainly due to different assumptions of population size, which was 19 million for the Greater Wuhan Area including surrounding cities by Wu et al. 9 versus 10 million for the Wuhan city in our analysis.