We declare no competing interests. L-LC and AW-HC contributed equally. This work was supported by Health and Medical Research Fund, the Food and Health Bureau, The Government of the Hong Kong Special Administrative Region (ref no. COVID190124 and COVID1903010 [Project 1]), the Emergency Collaborative Project (EKPG22-01) of Guangzhou Laboratory, and donations from Richard Yu and Carol Yu, Shaw Foundation Hong Kong, Michael Seak-Kan Tong, May Tam Mak Mei Yin, Lee Wan Keung Charity Foundation, Hong Kong Sanatorium and Hospital, Respiratory Viral Research Foundation, Hui Ming, Hui Hoy and Chow Sin Lan Charity Fund, Chan Yin Chuen Memorial Charitable Foundation, Marina Man-Wai Lee, the Hong Kong Hainan Commercial Association South China Microbiology Research Fund, the Jessie and George Ho Charitable Foundation, Kai Chong Tong, Tse Kam Ming Laurence, Foo Oi Foundation, Betty Hing-Chu Lee, and Ping Cham So. The funders had no role in study design, data collection, data analysis, data interpretation, or writing of the report. All authors had full access to all data in the study and had final responsibility for the decision to submit for publication. L-LC and KK-WT directly accessed and verified the underlying data. Data are available from the corresponding author upon reasonable request.