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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:
- 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).
- 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.
- 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.