CD4 and HIV infectious disease: Since as many as 70% of women in TFV PrEP trials used some form of chemical contraception, our findings that sex hormones alter TFV-DP in immune and non-immune cells from the FRT, when considered along with those of Coleman et al., provide compelling evidence that studies are needed to determine the extent to which intracellular TFV-DP within CD4+ T cells and macrophages in the FRT change with stage of the menstrual cycle and hormonal contraceptive use and whether these changes enhance or reduce susceptibility to HIV infection.