There are around 6 million doses of the Sinovac jab available, as the state of Rio de Janeiro made a deal with the Chinese manufacturer.
Efforts to import 2 million doses of the AstraZeneca/Oxford University vaccine from India initially failed on Friday, according to Deutsche press agency (dpa).
President Jair Bolsonaro and Rio de Janeiro's governor, Joao Doria, are in competition to become the first person to be photographed while receiving the jab.
Brazil is one of the countries hit hardest by the pandemic. Some 8.5 million people have caught the virus in the country of 210 million inhabitants, and more than 209,000 patients have died of Covid-19.
Due to the drastic increase in acute cases, the health system in Manaus in the Amazon region recently collapsed, with oxygen having to be airlifted into the metropolis.
