(Photo: Xinhua)

An epidemiological investigation shows two new COVID-19 cases confirmed in Shanghai on Friday are unrelated to a previous local case confirmed on November 9, but involve logistics personnel at the airport.

This point to an elevated risk of sporadic, logistics-related cases in the coming winter and spring, said Shanghai health authority and experts on Saturday.

After a married couple in Shanghai's Pudong New Area were confirmed to have contracted COVID-19 on Friday, 86 close contacts, including six relatives, are now in quarantine. As of Saturday morning, 8,120 people related to the couple have been screened and tested. Of the 4,468 test results that have been possessed so far, none have been positive.

Zhoupu township, where the couple live, has been labeled a mid-level risk area from which residents wanting to leave must hold a negative nucleic acid test certificate that was taken within the last seven days.

The husband, surnamed Wu, 39, works as an airport freight security checker at Shanghai Pudong International Airport, and his wife, surnamed Li, works as a nurse at Shanghai Pudong Hospital, which suspended daily outpatient and  emergency services.

Zhang Wenhong, a leading infectious disease specialist, noted at a press conference on Saturday that the local cases show there is risk of COVID-19 outbreaks during the coming winter and spring, especially in the logistics and cold chain sectors, and the entire country faces this risk.

"We cannot guarantee that there will be no further imported, sporadic and logistics related cases considering the current global pandemic," said Zhang, who assured the public of the city's effective overall response system, rapid tracking and accurate prevention and control capabilities.