13 reported that, among patients with a baseline CD4 count < 500 cells/μL, those who initiated cART within 4 months of their estimated date of infection experienced substantially higher CD4 cell levels over the first 4 years on treatment. Ding et al. 14 also reported a more rapid initial increase in CD4 count for patients in whom treatment was initiated within 2 months of diagnosis of a recent infection. Here, CD4 is linked to infection.