UK study suggests Delta subvariant less likely to cause symptoms

A subvariant of Delta that is growing in Britain is less likely to lead to symptomatic COVID-19 infection, a coronavirus prevalence survey found, adding that overall cases had dropped from a peak in October. The Imperial College London REACT-1 study, released on Thursday, found that the subvariant, known as AY.4.2, had grown to be nearly 12% of samples sequenced, but only a third had 'classic' COVID symptoms, compared with nearly a half of those with the currently dominant Delta lineage AY.4. Two-thirds of people with AY.4.2 had 'any' symptom, compared with more than three-quarters with AY.4.