Chinese researchers are testing mixing two Covid-19 vaccines developed by CanSino Biologics and a unit of Chongqing Zhifei Biological Products respectively, according to clinical trial registration data.

Earlier this month, the director of the Chinese Centre for Disease Control and Prevention said the country was "formally considering" giving people Covid-19 vaccines developed with different technologies as a way of further boosting vaccine efficacy.

A trial expected to involve 120 participants will test the safety and ability to trigger immune response of a dose of CanSinoBIO's Ad5-nCoV treatment, followed by a dose of ZF2001 from Anhui Zhifei Longcom Biopharmaceutical, at 28-day or 56-day interval, according to clinical trial record...