Preliminary results of late-stage trials in Brazil of CoronaVac, a potential vaccine against the Covid-19 virus developed by Sinovac Biotech Ltd of China, indicate that the vaccine is safe, Reuters reports, citing the Instituto Butantan, a Brazilian biomedical research centre.

The news agency quotes Butantan Institute Director Dimas Covas as saying that among the 9,000 Brazilians that CoronaVac has been tested on so far, none has shown any severe adverse reaction.

The director said 20 percent had felt mild pain from the injection.

The report quotes Governor João Doria of the state of São Paulo as saying the results prove that CoronaVac is the safest vaccine against Covid-19 being tested in Brazil, and the most promising.

The authorities in São Paulo hope the regulator will give permission this year for CoronaVac inoculations to begin there early next year, Reuters says.