Faculty members and students receive COVID-19 vaccines at a vaccination site at Anhui Agricultural University in Hefei, east China's Anhui Province, May 13, 2021.Photo:Xinhua

Sporadic COVID-19 cases reoccurred in the Chinese mainland on Thursday and Friday, 20 days after the mainland last reported any local infections.

Northeast China's Liaoning Province reported two local confirmed COVID-19 patients and three silent carriers in Yingkou city on Friday evening. 

Also on Friday, East China's Anhui Province found two new confirmed patients and one suspected case - a day after it had reported two confirmed cases on Thursday - taking the total number of local confirmed COVID-19 infections to four.

The newly reported cases (including the suspected one) in Anhui were all close contacts of the previous patients, local health authorities said on Friday evening.

Epidemiological investigations showed that two of the patients reported in Anhui - two females surnamed Li and Lü - had been to Yingkou recently, Yingkou's health authorities stated on Friday.

The two confirmed cases and three silent carriers in Yingkou, all staffers at a local photography studio, were close contacts of Li and Lü during their stay in the city, said Jin Li, deputy mayor of Yingkou, at a press release on Friday evening.

Nine residential communities and villages in Yingkou have been classified as "medium-risk areas" for COVID-19.

Yingkou has traced 264 close contacts and sub-contacts of Li and Lü, and has quarantined 217 people who had contact with the two patients.

The city has also collected 662 environmental samples for testing. Seven samples collected at the photography studio and a hotel tested positive for COVID-19, Jin said.

Global Times