A medical worker administers a dose of COVID-19 vaccine to an employee at a mobile vaccination site inside the Internet of Things technology industrial park in Hefei City of east China's Anhui Province, on May 21, 2021. (Xinhua/Du Yu)

BEIJING, May 23  -- More than 497.27 million doses of COVID-19 vaccines had been administered across China as of Saturday, the National Health Commission said Sunday.