Experts from the Imperial College London have discovered a feature of one of the branches of the "Delta" -strain

It is a subvariant of AY.4.2, which manifests itself differently from the main strain. During the study, 100,112 PCR tests for coronavirus taken from October 19 to November 5 of this year were checked. The "delta" -strain, both matrix and its branches, were found in 841 tests, 12% of which fell on subvariant AY.4.2.
But it was remarkable for scientists that only 33% of those infected with AY.4.2 had the standard symptoms of covid - persistent cough, loss or change of smell, taste, fever, etc.
According to researchers, this is an important discovery,which will allow you to better understand the nature of the virus. But it is also dangerous - when there are no obvious symptoms, a person may not suspect that they are sick and be a carrier of the virus.
Source: Izvestia