COVID-19 appears to be on the rise in some parts of California as a new, highly contagious subvariant — featuring “razor blade throat” symptoms overseas — is becoming increasingly dominant.

NB.1.8.1, a new COVID-19 variant that has caused concern among WHO officials, is now spreading in America, according to CDC data.

The UK is grappling with the rise of a new Covid strain known as Nimbus or NB. 1.8.1. Britain has seen an increase of almost 10 per cent in Covid-related hospital admissions in the final week of May amid cautions from the World Health Organisation (WHO).