MD Anderson Cancer Center proposed algorithm for management of refractory or resistant CMV infection with UL97 mutation(s). *While awaiting genotypic analysis results, maintaining GCV or VGCV and refraining from switching to FOS in low-risk patients (ie, HLA-identical HCT recipients without GVHD and/or without risk factors for CMV resistance) may be considered. EC50, concentration of a drug that gives half-maximal response; G-CSF, granulocyte colony-stimulating factor. Professional illustration by Patrick Lane, ScEYEnce Studios.