Quantification of human immunodeficiency virus type 2 (HIV-2) viral load in plasma: Comparison of three commercial assays.

Introduction: There are few validated commercially available HIV-2 assays for the measurement of viral load. Our aim was to compare three commercial assays for the quantification of HIV-2 viral load in plasma of patients with HIV-2 infection from our hospital.

Material and methods: We conducted a retrospective study at our tertiary-care hospital, analyzing samples from patients with known HIV-2 infection collected between 2022 and 2023. We compared three commercial assays for quantification of the viral load, Biomérieux® NASBA assay, Thermo Fisher® digital PCR (dPCR) assay and Altona® RT-PCR assay.

Results: A total of 27 samples from 11 different patients were included in the study. Sixteen out of them were negative across all three assays. One sample had a low viral load (<2 log copies/mL) detected by the three assays. In five samples a low viral load was only detected by the Altona® assay. The remaining five samples, all from the same patient infected by a multidrug-resistant HIV-2, showed detectable viral load up to 2 log copies/mL by the Thermo Fisher® and Altona® assays, but none of these samples were detected by the Biomérieux® assay.

Conclusions: The Altona® RT-PCR assay and the ThermoFisher® dPCR assay could be reliable options as commercial assays for the quantification of HIV-2 RNA in plasma. However, the Biomérieux® NASBA assay, despite detecting both HIV-1 and HIV-2, may have limitations for HIV-2 detection in some cases.