Characteristics of 563 Zambians who were HIV-1 seropositive at enrollment and 221 seroconverters who became seropositive during quarterly follow-up visits.

Dates (month/year) of seropositive tests, duration of follow-up (DOF, for SPs), and duration of infection (DOI, for SCs) are shown as median and interquartile range (in parentheses). The difference between patient groups is assessed using Mann-Whitney U test. All other comparisons between patient groups are based on Student's t-test (for quantitative measures) and χ2 test (for categorical measures). F  =  female; M  =  male; NA  =  not applicable; SD  =  standard deviation of the mean.