The east China city of Qingdao has seen the number of confirmed COVID-19 cases drop to zero, the local health commission said Thursday.

As of Wednesday, all the 14 patients reported since October 12 have been discharged from the hospital after recovery, according to the Qingdao municipal health commission.

Previously, investigations showed that inappropriate disinfection in the CT room of the Qingdao Chest Hospital led to the city's new cluster of infections after two asymptomatic patients underwent scans in the hospital's CT room. The two are stevedores, who had handled imported frozen seafood before, were diagnosed on September 24 as asymptomatic carriers of the novel coronavirus. They were being isolated at the Qingdao Chest Hospital.

Qingdao conducted a citywide nucleic acid testing covering all of its 11 million residents within five days to contain the spread of the virus.