Recent HIV-1 infection detection: comparison of incidence estimates derived by laboratory assays and repeat testing data.

INTRODUCTION: Advances in laboratory methods capable of detecting recent HIV infection offer the promise of quickly and efficiently measuring HIV incidence in cross-sectional surveys, thereby greatly expanding the capabilities of surveillance programs. We compared HIV-1 incidence estimates derived from 3 different methods: Vironostika-less sensitive, BED capture enzyme immuno assay (BED-CEIA), and repeat testing history.
METHODS: A cross-sectional analysis was performed using HIV testing data from the population of all men who have sex with men presenting for serological HIV voluntary counseling and testing at the largest testing programs in San Francisco from 2000 to 2004 (n = 15,010). Specimens were evaluated for recent HIV-1 infection using Vironostika-LS and BED-CEIA. Concordance between the 2 assays was assessed using the Kappa statistic.
RESULTS: The BED-CEIA and Vironostika-LS concurred in 90% of specimen classifications (Kappa = 0.77; "good" strength of agreement). Predictors of recent HIV-1 infection common to both methods were unprotected receptive anal intercourse (P < 0.001), sex with a known HIV-positive partner (P < 0.001), and amphetamine use (P < 0.01). Temporal trends in HIV-1 incidence were also consistent and stable.
CONCLUSIONS: There was good concordance in the classification of recent HIV-1 infection between BED-CEIA and Vironostika-LS and in the correlates of acquisition of infection. The findings suggest that these incidence assays can be used for the basic epidemiological purposes of measuring HIV-1 incidence, identifying populations at risk for infection, and tracking the leading edge of the epidemic over time.