Post-lockdown SARS-CoV-2 nucleic acid screening in nearly ten million residents of Wuhan, China

Cao, Shiyi; Gan, Yong; Wang, Chao; Bachmann, Max; Wei, Shanbo; Gong, Jie; Huang, Yuchai; Wang, Tiantian; Li, Liqing; Lu, Kai; Jiang, Heng; Gong, Yanhong; Xu, Hongbin; Shen, Xin; Tian, Qingfeng; Lv, Chuanzhu; Song, Fujian; Yin, Xiaoxv; Lu, Zuxun

Stringent COVID-19 control measures were imposed in Wuhan between January 23 and April 8, 2020. Estimates of the prevalence of infection following the release of restrictions could inform post-lockdown pandemic management. Here, we describe a city-wide SARS-CoV-2 nucleic acid screening programme between May 14 and June 1, 2020 in Wuhan. All city residents aged six years or older were eligible and 9,899,828 (92.9%) participated. No new symptomatic cases and 300 asymptomatic cases (detection rate 0.303/10,000, 95% CI 0.270–0.339/10,000) were identified. There were no positive tests amongst 1,174 close contacts of asymptomatic cases. 107 of 34,424 previously recovered COVID-19 patients tested positive again (re-positive rate 0.31%, 95% CI 0.423–0.574%). The prevalence of SARS-CoV-2 infection in Wuhan was therefore very low five to eight weeks after the end of lockdown.