Workers unload a batch of COVID-19 vaccines developed by the Chinese pharmaceutical company Sinovac at Cardinal Bernadin Gantin International Airport in Cotonou, Benin, March 21, 2021. A batch of coronavirus vaccine developed by the Chinese pharmaceutical company Sinovac arrived in Cotonou, the economic capital of Benin, on Sunday evening. (Photo by Seraphin Zounyekpe/Xinhua)

Benin's Health Minister Benjamin Hounkpatin and Chinese Ambassador to Benin Peng Jingtao attend a reception ceremony of a batch of coronavirus vaccine developed by the Chinese pharmaceutical company Sinovac at Cardinal Bernadin Gantin International Airport in Cotonou, Benin, March 21, 2021. A batch of coronavirus vaccine developed by the Chinese pharmaceutical company Sinovac arrived in Cotonou, the economic capital of Benin, on Sunday evening. (Photo by Seraphin Zounyekpe/Xinhua)

A plane carrying a batch of coronavirus vaccine developed by the Chinese pharmaceutical company Sinovac arrives at Cardinal Bernadin Gantin International Airport in Cotonou, Benin, March 21, 2021. A batch of coronavirus vaccine developed by the Chinese pharmaceutical company Sinovac arrived in Cotonou, the economic capital of Benin, on Sunday evening. (Photo by Seraphin Zounyekpe/Xinhua)

Workers unload a batch of COVID-19 vaccines developed by the Chinese pharmaceutical company Sinovac at Cardinal Bernadin Gantin International Airport in Cotonou, Benin, March 21, 2021. A batch of coronavirus vaccine developed by the Chinese pharmaceutical company Sinovac arrived in Cotonou, the economic capital of Benin, on Sunday evening. (Photo by Seraphin Zounyekpe/Xinhua)