Shanghai reported 234 confirmed COVID-19 cases, 2,780 asymptomatic cases and 6 deaths on Monday, health authorities announced on Tuesday.

During a news conference on Tuesday, Sun Xiaodong, deputy director of the Shanghai Center for Disease Control and Prevention, also explained the definition of close contacts, which refer to people who have been in contact with confirmed cases four days before the latter show symptoms. Those who have been in contact with asymptomatic cases four days before their test is taken are also considered close contacts.

Secondary contacts refer to those living, working or studying with the close contacts.

Sun noted that those living together with a COVID-19 case in an apartment with its own kitchen and toilet will be deemed as close contacts, while those living on the same floor and neighboring floors will be deemed as secondary contacts.

If a confirmed case lives in a building with communal kitchens and toilets, those living on the same floor will be deemed as close contacts, while the rest of the people in the building will be deemed secondary contacts.

"Each case must be handled with on-site investigation and risk evaluation. We should not resort to a simplistic and one-size-fits-all approach," Sun noted.

Jin Chen, deputy director of Shanghai Housing and Urban-Rural Development Commission, said that places where COVID-19 cases have resided must be disinfected. Community workers must communicate with the infected cases regarding the disinfection of their homes and find out what items need to be protected during the disinfection process.

Jin said that the homes of close contacts living in places with communal kitchens or bathrooms must be disinfected as well.