Covid-19 vaccines developed by China’s Sinovac Biotech are displayed during a press conference in Beijing on Sept. 24, 2020.Wang Zhao | AFP | Getty ImagesThe Covid-19 vaccine developed by China’s Sinovac Biotech is just 50.4% effective in a Brazilian trial — barely meeting the threshold for regulatory approval and well below the initially reported efficacy rate, according to several media reports. Brazil is the first to complete late-stage trial of the vaccine CoronaVac. The state-run Butantan Institute has been criticized by scientists and health experts for a lack of transparency in making public its trial data.The institute reportedly delayed releasing trial results three times — …
