Sinovac Biotech Ltd, the developer of CoronaVac Covid-19 vaccine, has defended the efficacy of its two-dose vaccine including against the Delta variant.

Company spokesperson Liu Peicheng said although no data is available on its protective effect yet, studies have proven the vaccine’s efficacy in countries such as Brazil, Indonesia, Chile and Turkey where the vaccine has been widely used.

“It was more than 90 percent effective against severe infection and hospitalisation. We also noticed that the infection rate after vaccination...