CoronaVac efficacy at 50-90% in Brazilian trial, says Sao Paulo official

The CoronaVac COVID-19 vaccine developed by China’s Sinovac Biotech Ltd showed efficacy between 50% and 90% in Brazilian trials, Sao Paulo's state health secretary said after concerns were raised by a failure to provide data on Wednesday.

Results of trials in Brazil are known exclusively by Sao Paulo state's Butantan Institute biomedical research center, which has an agreement with Sinovac to produce the vaccine, said health secretary Jean Gorinchteyn.

First trials showed efficacy above 50%, the minimum required by Brazilian health regulator Anvisa, and below 90%, Gorinchteyn said in an interview with CBN radio aired late on Thursday.

At Sinovac's request, Sao Paulo's health department hasn't received the Chinese drugmaker's full trial results, he said, adding that the company will review the data before announcing final results.

On Wednesday, Butantan had declined to specify the efficacy rate from a trial with 13,000 volunteers, citing its contractual obligations with Sinovac, raising questions about transparency.

The CoronaVac vaccine showed 91.25% efficacy in Turkey, according to an announcement on Thursday of interim data from a late-stage trial in the country.