The XEC COVID-19 variant, a sublineage of omicron, has spread to 27 countries, including Germany, UK, US, and Denmark. First identified in June, XEC is a hybrid of the KS.1.1 and KP.3.3 subvariants. It comes with new mutations that have enhanced its transmissibility. Experts believe this strain could dominate this winter, but stated that vaccines should still prevent severe cases.