HIV-1 Viral Load Assays for Resource-Limited Settings: Clades Matter

The paper by Fiscus et al. gives an excellent overview of current technologies to measure viral load (VL) and highlights the problems with finding assays that whilst affordable and practicable provide reliable and high-quality results to guide patient management in resource-constrained settings. One concern which in our mind does not receive enough attention in the paper is HIV variability. The assays ability to reliably quantitate non-B subtypes and strains is of paramount importance given the predominance of non-B HIV infections in developing countries. Unfortunately genotype bias has not been assessed systematically for most of the assays described in the paper. In our recent paper Ultrasensitive Monitoring of Viral Load by a Low-Cost Real-Time Reverse Transcription-PCR Assay with Internal Control for the 5 Long Terminal Repeat Domain (which is found by Fiscus et al.s PubMed search strategy for HIV-1 viral load AND resource-limited settings but presumably just missed the deadline for) we describe an inexpensive assay targeting the conserved long terminal repeat (LTR) domain of HIV-1. (excerpt)