A Chinese Covid-19 vaccine that is already being used in the country’s domestic vaccination campaign has been found to be nearly 82 per cent effective in a late stage clinical trial, the company said in an exchange filing on Friday.
A preliminary analysis of trial data also indicated the vaccine, developed by a unit of Chongqing Zhifei Biological Products, was able to hold up against the highly transmissible Delta variant, with almost 78 per cent efficacy.
The filing, which did not include detailed or peer-reviewed data, is the company’s first announcement of data from its large-scale trial. It could be a step toward full market approval for the three-dose vaccine, known as ZF2001, which received the green light for emergency use in China in March and is also being used in Uzbekistan.
The latest results come from an analysis of a phase three clinical trial that included 28,500 adults, split evenly between vaccines and placebos.
The trial took place in Uzbekistan, Pakistan, Indonesia, Ecuador and in China’s Hunan province, according to the Shenzhen-listed company’s filing.
The data, based on 221 Covid-19 cases among that group, found the vaccine was 81.76 per cent efficacious against Covid-19 of any degree of severity and had a 100 per cent efficacy rate against severe and fatal cases among participants.
The trial is expected to include robust data on efficacy in the elderly. Some 7,000 over-60s were slated to participate in the international study, according to the clinical trial registration, though no age breakdown for efficacy was yet reported.