Employees work on the production line of CoronaVac, Sinovac Biotech's vaccine against COVID-19 coronavirus at the Butantan biomedical production center, in Sao Paulo, Brazil, on January 14, 2021. - Sao Paulo state is due to begin immunizing its 12 million citizens from January 25. Beijing has already sent 10.7 million Coronavac doses and the supplies needed to make another 40 million doses. The health ministry, though, has yet to divulge when it will launch a nationwide immunization program. (Photo by NELSON ALMEIDA / AFP)