Fig. 1.

Paired HIV RNA levels in the blood (red) and cerebrospinal fluid (blue) compartments with respect to estimated days post HIV infection at initial sampling in antiretroviral naïve subjects with acute and primary HIV infection. Circles denote values measured in acute HIV subjects in Thailand with predominantly subtype CRF01_AE virus (adapted from [37], with permission); triangles denote values obtained in subjects from the USA, Sweden, Italy, and Australia with predominantly subtype B virus (updated from [38•], with permission). Note the approximately 15 percent of CSF samples with HIV RNA concentrations at or below the standard level of detection (50 copies/ml), often in the presence of high plasma HIV RNA, within the first 6 months after infection