Recent HIV-1 infection: identification of individuals with high viral load setpoint in a voluntary counselling and testing centre in rural Mozambique

Abstract

Background: Identification of recent HIV-infections is important for describing the HIV epidemic and compiling HIV-RNA-setpoint data for future HIV intervention trials. We conducted a study to characterize recent infections, and HIV-RNA-setpoint within the adult population presenting at a voluntary counselling and testing centre (VCT) in southern Mozambique.

Methods: All adults attending the Manhiça District-Hospital VCT between April and October 2009 were recruited if they had at least one positive rapid HIV-serology test. Patients were screened for recent HIV-1 infection by BED-CEIA HIV-incidence test. Clinical examination, assessment of HIV-RNA and CD4 cell counts were performed at enrollment, 4 and 10 months.

Results: Of the 492 participants included in this study, the prevalence of recent infections as defined by BED-CEIA test, CD4 counts >200 cells/µl and HIV-RNA >400 copies/mL, was 11.58% (57/492; 95% CI 8.89-14.74). Due to heterogeneity in HIV-RNA levels in recently infected patients, individuals were categorized as having "high" HIV-RNA load if their HIV-RNA level was above the median (4.98 log(10) copies/mL) at diagnosis. The "high" HIV-RNA group sustained a significantly higher HIV-viral load at all visits with a median HIV-RNA setpoint of 5.22 log(10) copies/mL (IQR 5.18-5.47) as compared to the median of 4.15 log(10) copies/ml (IQR 3.37-4.43) for the other patients (p = 0.0001).

Conclusion: The low proportion of recent HIV-infections among HIV-seropositive VCT clients suggests that most of this population attends the VCT at later stages of HIV/AIDS. Characterization of HIV-RNA-setpoint may serve to identify recently infected individuals maintaining HIV viral load>5 log10 copies/mL as candidates for antiretroviral treatment as prevention interventions.

Figure 1. Evolution of median HIV-RNA load and CD4∶CD8 ratios in recently infected patients.

HIV-RNA load (A) and CD4∶CD8 ratios (B) in patients with high HIV-RNA as compared to the other patients. Median and interquartile range are shown. HIV-RNA viral load groups are defined as described in methods. P-values are from Wilcoxon rank sum test between groups as follows: *p = 0.0001, **p = 0.038, *** p = 0.002. P-values from Wilcoxon Signed Rank between visits did not show significant differences. Numbers denote the n for each group at each time point.