Interestingly, genital inflammation is generally assessed in these studies after participants have abstained from sex for 48–72 h, despite the fact that the virus rapidly penetrates the genital epithelium after sex and is found in proximity to potential target cells within 4 h48, with important early targets for virus infection including CD4 + T cell subsets and immature dendritic cells11–13,17,49. Here, CD4 is linked to viral infectious disease.