People line up to get inoculated against the COVID-19 outside a mobile vaccination vehicle in Beibei District of southwest China's Chongqing, Aug. 20, 2021. Mobile vaccination vehicles were in service between 6 p.m. and 10 p.m. in some parts of Beibei District to facilitate COVID-19 vaccination. (Photos: Xinhua)

A man has his body temperature checked before getting inoculated against the COVID-19 outside a mobile vaccination vehicle in Beibei District of southwest China's Chongqing, Aug. 20, 2021. Mobile vaccination vehicles were in service between 6 p.m. and 10 p.m. in some parts of Beibei District to facilitate COVID-19 vaccination.

A woman gets inoculated against the COVID-19 in a mobile vaccination vehicle in Beibei District of southwest China's Chongqing, Aug. 20, 2021. Mobile vaccination vehicles were in service between 6 p.m. and 10 p.m. in some parts of Beibei District to facilitate COVID-19 vaccination.

A woman gets inoculated against the COVID-19 in a mobile vaccination vehicle in Beibei District of southwest China's Chongqing, Aug. 20, 2021. Mobile vaccination vehicles were in service between 6 p.m. and 10 p.m. in some parts of Beibei District to facilitate COVID-19 vaccination.

A medical worker helps a girl register for COVID-19 vaccination outside a mobile vaccination vehicle in Beibei District of southwest China's Chongqing, Aug. 20, 2021. Mobile vaccination vehicles were in service between 6 p.m. and 10 p.m. in some parts of Beibei District to facilitate COVID-19 vaccination.