A health worker of the Border Security Force receives a dose of the COVID-19 vaccine Covishield at Agartala, the capital city of India's northeastern state of Tripura, Jan. 21, 2021. (Str/Xinhua)

Health workers arrive at a hospital to give doses of the COVID-19 vaccine Covishield to health workers of the Border Security Force at Agartala, the capital city of India's northeastern state of Tripura, Jan. 21, 2021. (Str/Xinhua)

A health worker of the Border Security Force receives a dose of the COVID-19 vaccine Covishield at Agartala, the capital city of India's northeastern state of Tripura, Jan. 21, 2021. (Str/Xinhua)

A health worker prepares a dose of the COVID-19 vaccine Covishield for health workers of the Border Security Force at Agartala, the capital city of India's northeastern state of Tripura, Jan. 21, 2021. (Str/Xinhua)