Covid: Brazilian phase 3 study shows China's Sinovac jab has 50.7% efficacy

Sinovac Biotech Ltd.’s coronavirus vaccine cut in half the risk of developing symptomatic Covid-19 in a key Brazilian study, suggesting two doses of the shot is less potent than some other immunizations designed to tame the ongoing pandemic.

The study, which was posted online and hasn’t yet been reviewed by independent scientists, showed the vaccine was more effective at protecting against dangerous infections. None of those who received the CoronaVac injection developed severe disease.

The results of the trial involving 9,823 volunteers bolstered similar findings from a larger Brazilian study released last week that found a 50 per cent protection