A medical worker talks to a recipient before inoculating COVID-19 vaccine at a community health center in Taiyuan, north China's Shanxi Province, Jan. 15, 2021. (Xinhua/Cao Yang)

Medical workers inoculate recipients with COVID-19 vaccines at a community health center in Taiyuan, north China's Shanxi Province, Jan. 15, 2021. (Xinhua/Cao Yang)

A medical worker prepares to inoculate a recipient with COVID-19 vaccine at a community health center in Taiyuan, north China's Shanxi Province, Jan. 15, 2021. (Xinhua/Cao Yang)

Medical workers inoculate recipients with COVID-19 vaccines at a community health center in Taiyuan, north China's Shanxi Province, Jan. 15, 2021. (Xinhua/Cao Yang)

A medical worker inoculates a recipient with COVID-19 vaccine at a community health center in Taiyuan, north China's Shanxi Province, Jan. 15, 2021. (Xinhua/Cao Yang)

People wait in an observation area after receiving their COVID-19 vaccinations at a community health center in Taiyuan, north China's Shanxi Province, Jan. 15, 2021. (Xinhua/Cao Yang)

A medical worker inoculates a recipient with COVID-19 vaccine at a community health center in Taiyuan, north China's Shanxi Province, Jan. 15, 2021. (Xinhua/Cao Yang)