Covid-19: China’s CoronaVac vaccine offers 83.5% protection against symptomatic infection, interim analysis finds

Abstract

Two doses of the new CoronaVac vaccine made in China have an efficacy of 83.5% against symptomatic covid-19, an interim analysis has shown.1 The vaccine, developed by the Chinese company Sinovac Life Sciences and made from inactivated SARS-CoV-2 virus, shows promise for global distribution because of its relative stability. The phase III randomised controlled trial, conducted between September 2020 and January 2021 across 24 centres in Turkey, involved 10 218 participating adults between 18 and 59 years, randomly assigned to receive two doses of vaccine (6650) or placebo (3568). High risk healthcare workers as well as volunteers with an average covid-19 exposure risk in the community were recruited. Their average age was 45 years, and 58% were men. The interim analysis, published in the Lancet , showed that during a median follow-up period of 43 …