A woman measures blood pressure at a COVID-19 vaccination site of Jingcheng Hospital in Ruili City, southwest China's Yunnan Province, April 1, 2021. (Xinhua/Chen Xinbo)

A medical worker checks vaccine information at a COVID-19 vaccination site of Jingcheng Hospital in Ruili City, southwest China's Yunnan Province, April 1, 2021. (Xinhua/Chen Xinbo)

People queue for inoculation at a COVID-19 vaccination site of Jingcheng Hospital in Ruili City, southwest China's Yunnan Province, April 1, 2021. (Xinhua/Chen Xinbo)