A medical worker inoculates a citizen with a booster shot of COVID-19 vaccine at a vaccination clinic in Fanyu District of Guangzhou City, south China's Guangdong Province, Oct. 18, 2021. (Photo: Xinhua)

BEIJING, Oct. 20 (Xinhua) -- More than 2.236 billion doses of COVID-19 vaccines had been administered on the Chinese mainland as of Tuesday, data from the National Health Commission showed Wednesday.