People receive their COVID-19 vaccinations at a temporary vaccination site in Haidian District of Beijing, capital of China, Jan. 6, 2021. (Xinhua/Ju Huanzong)

A medical worker administers a shot of the COVID-19 vaccine to a man at a temporary vaccination site in Haidian District of Beijing, capital of China, Jan. 6, 2021. (Xinhua/Ren Chao)

A medical worker administers a shot of the COVID-19 vaccine to a man at a temporary vaccination site in Haidian District of Beijing, capital of China, Jan. 6, 2021. (Xinhua/Ren Chao)

A medical worker asks a man about his physical conditions after the COVID-19 vaccination at a temporary vaccination site in Haidian District of Beijing, capital of China, Jan. 6, 2021. (Xinhua/Ren Chao)

Staff members spray disinfectant in the observation area at a temporary vaccination site in Haidian District of Beijing, capital of China, Jan. 6, 2021. (Xinhua/Ren Chao)

A medical worker administers a shot of the COVID-19 vaccine to a delivery man at a temporary vaccination site in Haidian District of Beijing, capital of China, Jan. 6, 2021. (Xinhua/Ju Huanzong)

A medical worker administers a shot of the COVID-19 vaccine to a postman at a temporary vaccination site in Haidian District of Beijing, capital of China, Jan. 6, 2021. (Xinhua/Ju Huanzong)

A woman registers for the COVID-19 vaccination at a temporary vaccination site in Haidian District of Beijing, capital of China, Jan. 6, 2021. (Xinhua/Ren Chao)

A man registers for the COVID-19 vaccination at a temporary vaccination site in Haidian District of Beijing, capital of China, Jan. 6, 2021. (Xinhua/Zhang Yuwei)

A medical worker guides people who come for the COVID-19 vaccination at a temporary vaccination site in Haidian District of Beijing, capital of China, Jan. 6, 2021. (Xinhua/Lu Ye)

People receive their COVID-19 vaccinations at a temporary vaccination site in Haidian District of Beijing, capital of China, Jan. 6, 2021. (Xinhua/Ju Huanzong)

A medical worker prepares to administer a shot of the COVID-19 vaccine to a woman at a temporary vaccination site in Haidian District of Beijing, capital of China, Jan. 6, 2021. (Xinhua/Lu Ye)

People register for their COVID-19 vaccinations at a temporary vaccination site in Haidian District of Beijing, capital of China, Jan. 6, 2021. (Xinhua/Ren Chao)

People wait in an observation area after receiving their COVID-19 vaccinations at a temporary vaccination site in Haidian District of Beijing, capital of China, Jan. 6, 2021. (Xinhua/Ren Chao)

A medical worker administers a shot of the COVID-19 vaccine to a man at a temporary vaccination site in Haidian District of Beijing, capital of China, Jan. 6, 2021. (Xinhua/Lu Ye)

A medical worker prepares for the COVID-19 vaccination at a temporary vaccination site in Haidian District of Beijing, capital of China, Jan. 6, 2021. (Xinhua/Zhang Yuwei)

A man registers for the COVID-19 vaccination at a temporary vaccination site in Haidian District of Beijing, capital of China, Jan. 6, 2021. (Xinhua/Ren Chao)