The recent local COVID-19 infection cases in Guangzhou, Guangdong province, are all related to the 75-year-old patient surnamed Guo who was reported on May 21, forming one transmission chain.

Since May 21, four COVID-19 patients, including Guo, and five asymptomatic carriers have been reported in Guangzhou. Guo lived or dined with the other eight, said Chen Bin, deputy director of the city's health commission, at a news conference on Thursday.

The nine are being treated at hospital. A total of 487 people with close contact with them have been identified and tested.

Nucleic acid tests had been conducted on 546,000 people by 2 pm on Thursday since May 21 and all the 240,900 test results received so far are negative.

By noon on Thursday, 8.67 million people in Guangzhou had received the COVID-19 vaccine, 2.99 million of whom having got the required two shots each, Chen said.

To prevent infection in clinics, the authorities have inspected 1,114 clinics since May 21 and ordered the closure of 79 of them for failing to meet the standard. Medical institutions without a fever clinic or fever room are prohibited from accepting patients with a fever, she said.