A medical worker collects a swab sample of a student for nucleic acid testing at a primary school in Lu'an, east China's Anhui Province, May 17, 2021.(Photo: Xinhua)

The virus that caused the fresh cluster of COVID-19 infections in East China's Anhui and Northeast China's Liaoning provinces was either from infected overseas travelers or contaminated imported products, and authorities are tracing its source, Chinese Center for Disease Control and Prevention (CDC) said on Thursday. 

China currently has no domestic COVID-19 cases and the virus of the fresh cluster infection must have come from overseas, either from infected people or contaminated products. Wu Zunyou, chief epidemiologist of China CDC, said at Thursday's press conference.

Wu said that the virus found in Anhui has the same genetic sequence as the virus found in Liaoning, and the virus in both provinces was on the same transmission chain. 

As for possible asymptomatic infections, Wu said that silent carriers are less infectious, and the virus that they carry can only spread after frequent and long-term contact, and will not result in consecutive first and second generation infections. 

The cluster infections in Anhui have resulted in seven domestic confirmed cases and 11 asymptomatic cases since the first case was reported on May 13, Anhui health authority said on Thursday.

Wu said that antibody tests from 10 cases in Anhui all came back negative, indicating patients in these cases have been infected for a short time, and the scale of the fresh cluster of infections will not be bigger than the infections early this year. 

The genetic sequencing of patient specimens in Anhui found no mutations that caused high pathogenicity or high infectiousness. The variant does not belong to the highly infectious variants currently prevalent in India or South Africa, officials from the Anhui health commission said.

Global Times