aged between 18 and 75 years from three hospitals in Wenzhou, China (the First Affiliated Hospital of Wenzhou Medical University, Wenzhou Central Hospital, and Ruian People's Hospital) between January 1, 2020 and February 29, 2020. COVID-19 was diagnosed as a positive result by high-throughput sequencing or real-time reverse transcriptase-polymerase chain reaction assay of oropharyngeal swab specimens.