CanSino Biologics Inc's vaccine was 57.5% effective against symptomatic Covid-19 and 91.7% against severe disease four weeks or longer after one dose, while its protection appeared lower in older people, peer-reviewed results from a large trial showed.

The single-shot Ad5-nCoV vaccine, which CanSinoBIO co-developed with the Chinese military-backed Beijing Institute of Biotechnology, has been approved for use in countries such as China, Mexico and Pakistan.

The efficacy of 57.5% against symptomatic Covid-19, meaning it reduced the risk of symptomatic disease by 57.5% for vaccinated people...