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.

The UK has reported cases of the new Covid variant, Nimbus or NB. 1.8.1, with a rise in Covid-related hospital admissions by almost 10% in the last week of May, following a warning from the World Health Organisation (WHO). Sufferers of the new variant have described a "razor blade throat" symptom.

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.