Source: South China Morning PostChinese drug maker Sinovac’s CoronaVac shot reduces the risk of symptomatic Covid-19 infections by half, in line with previous data, according to the long-awaited results of a phase three clinical trial in Brazil.The trial by Brazil’s state-owned research institute Butantan involved 9,823 health care workers, who received two doses of the vaccine. The primary efficacy against symptomatic Covid-19 infection was 50.7 per cent, according to the study, which was published on Sunday but has not yet…Read More