Population Viral Load, Viremia and Recent HIV-1 Infections: Findings from Population-based HIV Impact Assessments (PHIAs) in Zimbabwe, Malawi, and Zambia.

BACKGROUND HIV population viral load (PVL) can reflect antiretroviral therapy (ART) program effectiveness and transmission potential in a community. Using nationally representative data from household surveys conducted in Zimbabwe, Malawi, and Zambia in 2015-16, we examined the association between various VL measures and the probability of at least one recent HIV-1 infection in the community. METHODS We used Limiting-antigen (LAg) Avidity enzyme immunoassay (EIA), VLS (HIV RNA <1000 copies/mL), and ARVs in the blood to identify recent HIV-1 cases. RESULTS Among 1,510 EAs across the three surveys, 52,036 adults aged 15-59 years resided in 1,363 (90.3%) EAs with at least one HIV-positive adult consenting to interview and blood draw and whose VL was tested. Mean HIV prevalence across these EAs was 13.1% (95% confidence intervals [CI] 12.7-13.5). Mean VLS prevalence across these EAs was 58.7% (95% CI 57.3-60.0).In multivariable analysis, PVL was associated with a recent HIV-1 case in that EA (adjusted odds ratio [AOR]: 1.4, 95% CI 1.2-1.6, p=0.001). VLS prevalence was inversely correlated with recent infections (AOR: 0.3, 95% CI 0.1-0.6, p=0.004). The 90-90-90 indicators, namely, the prevalence of HIV diagnosis, ART coverage, and VLS at the EA level, were inversely correlated with HIV recency at the EA level. CONCLUSION We found a strong association between PVL and VLS prevalence and recent HIV-1 infection at the EA level across three southern African countries with generalized HIV epidemics. These results suggest that population-based measures of VLS in communities may serve as a proxy for epidemic control.