Workers unload the COVID-19 vaccine donated by China at an airport in Freetown, Sierra Leone, on Feb. 25, 2021. Sierra Leone on Thursday received a consignment of 200,000 doses of China's Sinopharm COVID-19 vaccine donated by China to support the country's vaccination campaign. (Photo: Xinhua)

Photo taken on Feb. 25, 2021 shows a consignment of the Sinopharm COVID-19 vaccine donated by China at an airport in Freetown, Sierra Leone. Sierra Leone on Thursday received a consignment of 200,000 doses of China's Sinopharm COVID-19 vaccine donated by China to support the country's vaccination campaign. (Photo: Xinhua)

Workers unload the COVID-19 vaccine donated by China at an airport in Freetown, Sierra Leone, on Feb. 25, 2021. Sierra Leone on Thursday received a consignment of 200,000 doses of China's Sinopharm COVID-19 vaccine donated by China to support the country's vaccination campaign. (Photo: Xinhua)

Chinese Ambassador to Sierra Leone Hu Zhangliang (R) attends a handover ceremony of the Sinopharm COVID-19 vaccine donated by China at an airport in Freetown, Sierra Leone, on Feb. 25, 2021. Sierra Leone on Thursday received a consignment of 200,000 doses of China's Sinopharm COVID-19 vaccine donated by China to support the country's vaccination campaign. (Photo: Xinhua)