Britain's medicines regulator has approved AstraZeneca's antibody-based Covid-19 treatment for preventing infections in adults with poor immune response, marking a major step in the fight against the pandemic as infections surge globally.

The decision to grant approval for the treatment, Evusheld, was endorsed by the government's independent scientific advisory body, Britain's Medicines and Healthcare products Regulatory Agency (MHRA) said, according to Reuters.

The therapy was found to cut the risk of developing symptomatic Covid-19 by 77 per cent in trials, with protection lasting for at least six months after a single dose, the MHRA said.