A medical worker introduces precautions to a COVID-19 vaccine recipient at the No. 1 People's Hospital in Xining, northwest China's Qinghai Province, Jan. 5, 2021. The COVID-19 inoculation in Qinghai currently mainly covers nine key groups of people, including medical workers, customs inspectors and community workers. (Photos: Xinhua)

A medical worker takes a COVID-19 vaccine out of refrigerator at the No. 1 People's Hospital in Xining, northwest China's Qinghai Province, Jan. 5, 2021. The COVID-19 inoculation in Qinghai currently mainly covers nine key groups of people, including medical workers, customs inspectors and community workers.

A medical worker inoculates a recipient with a COVID-19 vaccine at the No. 1 People's Hospital in Xining, northwest China's Qinghai Province, Jan. 5, 2021. The COVID-19 inoculation in Qinghai currently mainly covers nine key groups of people, including medical workers, customs inspectors and community workers.