With cases growing at two percent a week, it is expected to quickly take over – but is less likely to cause serious illness. Known as AY.4.2, it features in one in six cases in England, up from one in eight a fortnight ago. Scientists say it is up to 15 percent more transmissible than the original Indian Delta variant. But a study found only 66.7 percent who catch AY.4.2 have symptoms compared with 76.4 percent with Delta.
The new subvariant is believed to be from London or the South-east and has two slight changes to its spike protein.
It makes up the biggest proportion of cases in the Southwest, an area with the highest infection rate in England at 516.2 cases per 100,000.
Dr Jeffrey Barrett, an expert at the Sanger Institute, said he expects the subvariant to become dominant in January.
Paul Hunter, of the University of East Anglia, repeated the belief that Covid will become endemic, like “a common cold”.