LONDON (Reuters) -Britain announced new measures on Saturday to try to slow the spread of the newly identified Omicron coronavirus variant and a top health official said there was a "reasonable chance" that vaccines could be less effective against it.
Prime Minister Boris Johnson said arrivals from all countries would have to self-isolate until receiving a negative result from a PCR test, that face masks must be worn in retail settings and it was time to step up booster jabs.
