Britons have been urged to wear masks in crowded public spaces and isolate if they test positive for Covid, amid a spike in cases of two new variants of the virus. The strains—XFG, dubbed Stratus, and NB.1.8.1, known as Nimbus—are fuelling a surge in infections, with cases doubling since August. Professor Lawrence Young, a virologist at Warwick University told the Daily Mail the increase in cases and hospitalisations is 'worrying so early in the Autumn period'. He put it down to a mixture of children returning to school, colder temperatures causing people to spend more time indoors—often in places with...