Brazil trial finds efficacy of Sinovac vaccine at 50.4 percent
A coronavirus vaccine developed by China’s Sinovac Biotech was found to be just 50.4 percent effective at preventing symptomatic infections of COVID-19 in a Brazilian trial, researchers said on Tuesday, barely enough for regulatory approval and well below the rate announced last week.
The latest results are a substantial disappointment for Brazil, as the Chinese vaccine is one of two that the federal government has lined up to begin immunisation during the second wave of the world’s second-deadliest COVID-19 outbreak.
Several scientists and observers criticised the Butantan Institute, a biomedical centre for releasing partial data just days ago that generated unrealistic expectations. The confusion may add to scepticism in Brazil about the Chinese vaccine, which President Jair Bolsonaro has criticised, questioning its “origins.”
“We have a good vaccine. Not the best vaccine in the world. Not the ideal vaccine,” said microbiologist Natalia Pasternak, criticising Butantan’s triumphant tone.
Last week, the Brazilian researchers had celebrated results showing 78 percent efficacy against “mild to severe” COVID-19 cases, a rate they later described as “clinical efficacy.”