The XEC variant is the product of a recombination (exchanged pieces of genetic material between two variants) between the KS.1.1 variant and the KP.3.3 variant. These two parent variants are closely related, having both evolved from JN.1, which was the dominant variant around the world at the start of 2024.

This scanning electron microscope image shows SARS-CoV-2 (yellow)—also known as 2019-nCoV, the virus that causes COVID-19—isolated from a patient in the U.S., emerging from the surface of cells (blue/pink) cultured in the lab.