The Chinese mainland reported 328 cases of local COVID-19 transmissions in July as of 3 p.m. on Saturday, almost the totality of the five previous months, a spokesperson for the China National Health Commission said at a Saturday press conference.

A recent virus outbreak involving the Delta variant has spread to 14 provincial-level regions, Mi Feng added. 

All nine people in a critical condition with COVID-19 in east China's Nanjing City as of Saturday morning were infected with the more contagious Delta variant, health official Guo Yanhong said.

A total of 262 cases reported across China as of Friday morning have been linked to cluster infections in Nanjing Lukou International Airport. Mi said that summer holiday travel had also contributed to the resurgence of COVID-19 cases. 

The first confirmed local infection in central China's tourist city Zhangjiajie in the latest outbreak was spread from Nanjing, said Feng Zijian, deputy director of the Chinese Center for Disease Control and Prevention. The new epicenter has imposed a lockdown in residential complexes and closed entertainment venues and tourist sites to curb the spread of the virus.

Nearly 1.64 billion doses of COVID-19 vaccines had been administered across China as of Friday.

China's COVID-19 vaccines are effective for the variants despite some vaccinated people getting infected, said Shao Yiming, a researcher at the Chinese Center for Disease Control and Prevention. They can reduce the rate of infections with severe syndrome and fatality rate, Shao added.

People should take the same type of vaccine made by the same manufacturer, Wang Huaqing, an expert from the Chinese Center for Disease Control and Prevention said at the press conference.

(Cover: A person takes a COVID-19 test in a makeshift site in Zhangjiajie, Hunan, central China, July 29, 2021. /CFP)