Huaiyu Tian 1 , † , Yonghong Liu 1 , Yidan Li 1 , Chieh-Hsi Wu 3 , Bin Chen 4 , Moritz U. G. Kraemer 2 , 5 , 6 , Bingying Li 1 , Jun Cai 7 , Bo Xu 7 , Qiqi Yang 1 , Ben Wang 1 , Peng Yang 8 , Yujun Cui 9 , Yimeng Song 10 , Pai Zheng 11 , Quanyi Wang 8 , Ottar N. Bjornstad 12 , 13 , Ruifu Yang 8 , † , Bryan T. Grenfell 14 , 15 , † , Oliver G. Pybus 2 , † , Christopher Dye 2 , †
31 March 2020
Responding to an outbreak of a novel coronavirus (agent of COVID-19) in December 2019, China banned travel to and from Wuhan city on 23 January and implemented a national emergency response. We investigated the spread and control of COVID-19 using a unique data set including case reports, human movement and public health interventions. The Wuhan shutdown was associated with the delayed arrival of COVID-19 in other cities by 2.91 days (95%CI: 2.54-3.29). Cities that implemented control measures pre-emptively reported fewer cases, on average, in the first week of their outbreaks (13.0; 7.1-18.8) compared with cities that started control later (20.6; 14.5-26.8). Suspending intra-city public transport, closing entertainment venues and banning public gatherings were associated with reductions in case incidence. The national emergency response appears to have delayed the growth and limited the size of the COVID-19 epidemic in China, averting hundreds of thousands of cases by 19 February (day 50).