Britain will offer a Covid-19 booster shot to all adults in a bid to accelerate its vaccination programme amid concern over the new Omicron coronavirus variant, as eight more cases were found in the country.

Britain as a whole has reported 11 cases of the new variant, which the WHO said on Monday was likely to spread internationally and posed a very high risk of infection surges.

British Prime Minister Boris Johnson has responded to the emergence of Omicron by making mask-wearing compulsory in shops and on public transport in England.

He also asked the Joint Committee on Vaccination and Immunisation to review the booster programme, which is currently open to over-40s, the vulnerable and health workers.

The JCVI recommended on Monday that boosters be offered to all adults under 40, that the minimum gap between second doses and boosters could be reduced to three months from six, and that 12- to 15-year-olds could get a second shot.