The city reported four locally transmitted COVID-19 cases, 979 local asymptomatic infections, 10 imported patients and three imported asymptomatic cases on Wednesday, said the Shanghai Health Commission on Thursday morning.Of all the local infections, four confirmed patients and 878 asymptomatic cases were detected during central quarantine, while the rest were found in the screening of high-risk people.4 local casesAll the four patients tested positive during central quarantine.