(Yicai Global) May 7 -- Shanghai detected one more imported novel coronavirus case yesterday, taking the eastern metropolis' total of confirmed cases to 657, the city's health commission said this morning.

The new addition, a Chinese citizen who had been studying in the United States, traveled back to Shanghai on May 4, according to the commission.

Authorities have traced 69 people who had been in contact with the patient during their journeys and placed them under quarantine, the commission added.

The commission confirmed no new domestically transmitted cases yesterday. It also reported no asymptomatic cases under observation in the city the same day.

Among the confirmed 318 imported Covid-19 cases so far, 30 patients are being treated, with two in serious condition, and 288 have been discharged upon recovery, the commission said.

It added three suspected cases, also involving people who had recently been overseas, are undergoing further tests.

Of the 339 local cases, seven have died and 332 patients have fully recovered and been released from hospital, the commission said.