Calibration and Application of a Simple Sensitive/Less Sensitive Assay Applicable to Resource-Limited Countries for Determination of Recent HIV Infection and Incidence Estimates

This study was terminated March 31, 2007.

Sensitive/Less Sensitive assays (S/LS) to distinguish between recent and established HIV infections have been successfully applied to identify recently infected persons and determine HIV incidence. However, all currently used S/LS assays require laboratory instrumentation which limit their applicability in resource poor countries where stable electricity and laboratory infrastructure are lacking. Similarly, these assays require a high degree of technical expertise that is limited in a majority of laboratories throughout the world, and the cost of these tests is relatively high. More technically simple, cost-effective, and robust assays are needed to promote the use of S/LS assays by a larger range of users and for use where non-B HIV clades exist. The Serodia HIV-1/IHIV-2 particle agglutination assay (PA), a simple HIV assay that is used globally and can be performed by non-HIV specialists, has been modified by the University of Maryland investigators as an S/LS assay and shown to possess a high positive predictive value for detecting truly recently infected individuals, and a 97% sensitivity for classifying recent and established infection specimens when tested on seroconversion panels for clade B HIV viruses at a cost 30 times lower than other S/LS tests.   

The aims of this study were to:

1. Calibrate a simple particle agglutination assay as a less sensitive test (PA LS) using well-characterized specimens derived from seroconverting persons to distinguish recent from established HIV infection in epidemics harboring clades C (India), and A/G (Nigeria).
2. Apply the calibrated PA LS test to measure the HIV incidence using surveillance data and banked seropositive specimens that are collected from 5 well-characterized high risk populations in Nigeria.
3. Identify parameters of the PA LS assay, for each clade, that give the greatest predictive value for identifying recently infected individuals for eligibility into early intervention programs.