Two Covid-19 vaccine candidates developed by units of China National Biotec Group (CNBG) to target the Omicron variant were approved for clinical trials as boosters in Hong Kong, the Sinopharm subsidiary said today.

Scientists worldwide are racing to study upgraded injections against Omicron, as data indicated that antibodies elicited by vaccines based on older strains show weaker activity to neutralise the highly transmissible variant.

The two candidates, both containing...