One distinguishing factor is that XEC is a recombinant strain, a hybrid resulting from the merger and rearrangement of two existing COVID subvariants, Omicron sublineage KP.3.3 (descendant of the FLiRT variant) and KS.1.1. That's true.
Such mergers can occur when one person is infected with two different strains. “So rather than slowly progressing one mutation at a time, as we've seen with mutant strains of SARS-CoV-2, this has the potential to be a major breakthrough. “combines complete segments of two genomes into one new genome,” says Dr. Roberts.
However, he added that a “big leap forward” has yet to be seen and is probably still unlikely.
Another difference is that the XEC strain has at least one new mutation in the spike protein in addition to those found in these two strains, but it is currently unclear how this will affect infected people. But Omicron and its subvariants generally cause milder disease than strains that emerged early in the pandemic, such as Alpha and Delta, and symptoms remain unchanged, Dr. Roberts said.
According to the CDC, symptoms still include (but are not limited to) cough, stuffy or runny nose, diarrhea, fever or chills, shortness of breath, and loss of taste or smell. Symptoms may be mild at first, but in some people they may become severe as the disease progresses. “We don't see any change in the behavior of the virus other than increased transmissibility,” Dr. Roberts said.
