The variant in question, which is associated with severe COVID-19, is located on chromosome 3 in a region that encodes for chemokine receptors. Individuals who carry the factor have decreased levels of the chemokine receptors CCR3, CCR5, and CXCR6, which was the clue to the link with HIV infection, since low values of these three receptors are associated with a lower prevalence of HIV infection, according to the paper's author, Hugo Zeber, PhD, of the Max Planck Institute for Evolutionary Anthropology. February 24, 2022
