A coronavirus vaccine developed by China's Sinovac Biotech was 78 percent effective in a late-stage Brazilian trial, with no severe COVID-19 cases occurred among those volunteers, researchers said on Thursday.

Dimas Covas, director of the Brazilian biomedical center Butantan, Sinovac's research and production partner, said detailed results were being submitted to health regulator Anvisa as part of a request for emergency use of the vaccine.

(With input from Reuters)