FIG. 1.

Laboratory staging of acute and early HIV-1 infections. (A) Temporal appearance of HIV-1-specific laboratory markers following HIV-1 infection according to the classification system of Fiebig et al. (8). The eclipse phase is defined by the interval between transmission and first detection of vRNA in the plasma and generally lasts about 10 days, with a range of approximately 7 to 21 days (3, 10, 17-19, 40). The mean durations of Fiebig stages I (7 days), II (5 days), III (3 days), IV (6 days), and V/VI (70+ days) are indicated. (B) Time points (x axis) at which plasma samples were obtained for each of the 12 study subjects (y axis). Because subjects were studied at intervals of ∼3 months, the symbols are positioned to represent the maximum possible number of days from transmission.