CD4 and HIV infectious disease: This period is similar to the period of unchecked viral replication reported in adult-acquired HIV infection prior to starting treatment (approximately eight years to a CD4 count threshold of <200 cells/μL).[34] Despite this, CD4:CD8 recovery in yp-PaHIV more closely resembled the immune profile in adults where there was a maximum of six months of unchecked viremia.[13] Immunological maturation in the presence of a replicating CD4-tropic virus will impact upon subsequent measures of immune recovery in perinatally acquired HIV infection, (reviewed in [35]).