Two resdients ride motocycles along a street in front of  a UPS building in Shanghai. Photo: Yang Hui/GT

The COVID-19 strain from samples of the six local cases confirmed from November 20 to 23 in Shanghai is the same as that which is prevalent in Europe, indicating the infection source of those cases was from overseas, a Shanghai government official said during a press conference on Monday.

The virogene type of the six cases is the same as a branch of strains from Europe, indicating that the infection source was either aviation facilities or overseas persons, Sun Xiaodong, deputy director of the Shanghai Center for Disease Control and Prevention, said during a press conference on Monday in Shanghai.

But Sun added the virus strain is different from the first two cases reported from November 9 and 10.

From November 9 to 23, a total of eight local cases were reported related to Pudong International airport. On November 9, Shanghai found the first new local COVID-19 case in Pudong New Area after months without any local infections. The local case and his colleague, who was confirmed infected the next day, in East China's Anhui Province, were infected with a virus strain similar to that from North America, according to Shanghai authorities. 

Among the six cases, three of them work at the same delivery companies and come into close contact during work. One of them had close contact with flight personnel and related environments from overseas 14 days before he showed syndromes. The other two cases were family members of the confirmed cases.