A coronavirus vaccine developed by China's Sinovac showed “general efficacy” of 50.38 per cent in a late-stage trial in Brazil, the company's local partners said, revealing a more modest figure after pressure for more transparency.
On Thursday, Butantan officials had celebrated results showing 78pc efficacy against mild Covid-19 cases, a rate they have since described as “clinical efficacy”.
Ricardo Palacios, medical director for clinical research at the Butantan biomedical centre in Sao Paulo, said the new figure included infections that were so mild or asymptomatic that they did not need clinical care.
