Medical workers administer the COVID-19 vaccine to recipients in Colombo, Sri Lanka, on Aug. 24, 2021. Sri Lanka's Health Ministry said on Tuesday that 25 percent of the country's total population had received both doses of the COVID-19 vaccines while 55 percent of the total population had been administered the first dose. (Photo by Ajith Perera/Xinhua)

A man receives the COVID-19 vaccine in Colombo, Sri Lanka, on Aug. 24, 2021. Sri Lanka's Health Ministry said on Tuesday that 25 percent of the country's total population had received both doses of the COVID-19 vaccines while 55 percent of the total population had been administered the first dose. (Photo by Ajith Perera/Xinhua)

A pregnant mother receives the COVID-19 vaccine at a maternity clinic in Colombo, Sri Lanka, on Aug. 24, 2021. Sri Lanka's Health Ministry said on Tuesday that 25 percent of the country's total population had received both doses of the COVID-19 vaccines while 55 percent of the total population had been administered the first dose. (Photo by Ajith Perera/Xinhua)

Pregnant mothers wait to receive the COVID-19 vaccine at a maternity clinic in Colombo, Sri Lanka, on Aug. 24, 2021. Sri Lanka's Health Ministry said on Tuesday that 25 percent of the country's total population had received both doses of the COVID-19 vaccines while 55 percent of the total population had been administered the first dose. (Photo by Ajith Perera/Xinhua)