People line up to get administered against the COVID-19 at a vaccination site in Johannesburg, South Africa, Aug. 20, 2021. The South African government began vaccinating people aged 18 to 34 from Friday. (Xinhua/Chen Cheng)

People walk into a vaccination venue to get administered against the COVID-19 in Johannesburg, South Africa, Aug. 20, 2021. The South African government began vaccinating people aged 18 to 34 from Friday. (Xinhua/Chen Cheng)

People line up to get administered against the COVID-19 at a vaccination site in Johannesburg, South Africa, Aug. 20, 2021. The South African government began vaccinating people aged 18 to 34 from Friday. (Xinhua/Chen Cheng)

People line up to get administered against the COVID-19 at a vaccination site in Johannesburg, South Africa, Aug. 20, 2021. The South African government began vaccinating people aged 18 to 34 from Friday. (Xinhua/Chen Cheng)

People line up to get administered against the COVID-19 at a vaccination site in Johannesburg, South Africa, Aug. 20, 2021. The South African government began vaccinating people aged 18 to 34 from Friday. (Xinhua/Chen Cheng)

A volunteer checks information of a COVID-19 vaccine recipient at a vaccination site in Johannesburg, South Africa, Aug. 20, 2021. The South African government began vaccinating people aged 18 to 34 from Friday. (Xinhua/Chen Cheng)