It must be noted, however, that a preferential selection of the X4 variants in CCR5 Δ32/wt cases is also possible; to date, there is no conclusive data on whether the presence of the Δ32 allele is associated with lower susceptibility to R5 infections or favours a switch to CXCR4 using clades. Here, CXCR4 is linked to infection.