HIV risk behaviour, viraemia, and transmission across HIV cascade stages including low-level viremia: Analysis of 14 cross-sectional population-based HIV Impact Assessment surveys in sub-Saharan Africa
Authors: Edun Olanrewaju , Okell Lucy , Chun Helen , Bissek Anne-Cecile Z. , Ndongmo Clement B. , Shang Judith D. , Brou Hermann , Ehui Eboi , Ekra Alexandre K. , Nuwagaba-Biribonwoha Harriet , Dlamini Sindisiwe S. , Ginindza Choice , Eshetu Frehywot , Misganie Yimam G. , Desta Sileshi Lulseged , Achia Thomas N. O. , Aoko Appolonia , Jonnalagadda Sasi , Wafula Rose , Asiimwe Fred M. , Lecher Shirley , Nkanaunena Kondwani , Nyangulu Mtemwa K. , Nyirenda Rose , Beukes Anita , Klemens Johannes O. , Taffa Negussie , Abutu Andrew A. , Alagi Matthias , Charurat Man E. , Dalhatu Ibrahim , Aliyu Gambo , Kamanzi Collins , Nyagatare Celestine , Rwibasira Gallican N. , Jalloh Mohamed F. , Maokola Werner M. , Mgomella George S. , Kirungi Wilford L. , Mwangi Christina , Nel Jennifer A. , Minchella Peter A. , Gonese Gloria , Nasr Melodie A. , Bodika Stephane , Mungai Elisabeth , Patel Hetal K. , Sleeman Katrina , Milligan Kyle , Dirlikov Emilio , Voetsch Andrew C. , Shiraishi Ray W. , Imai-Eaton Jeffrey W. 
Published: April 2024

As antiretroviral treatment (ART) coverage for people living with HIV (PLHIV) increases, HIV programmes require up-to-date information about evolving HIV risk behaviour and transmission risk, including those with low-level viremia (LLV; >50 to ≤1000 copies/mL), to guide prevention priorities. We aimed to assess differences in sexual risk behaviours, distribution of viral load (VL) and proportion of transmission across PLHIV subgroups. We analysed data from Population-based HIV Impact Assessment surveys in 14 sub-Saharan African countries during 2015–2019. We estimated adjusted prevalence ratios (aPR) of self-reported HIV high-risk behaviour (multiple partners and condomless sex) across cascade stages via generalised estimation equations. We modelled the proportions of transmission from each subgroup using relative self-reported sexual risk, a Hill function for transmission rate by VL, and proportions within cascade stages from surveys and UNAIDS country estimates for 2010–2020. Compared to PLHIV with undetectable VL (≤50 copies/mL), undiagnosed PLHIV (aPR women: 1.28 [95% CI: 1.08–1.52]; men: 1.61 [1.33–1.95]) and men diagnosed but untreated (2.06 [1.52–2.78]) were more likely to self-report high-risk sex. High-risk behaviour was not significantly associated with LLV. Mean VL was similar among undiagnosed, diagnosed but untreated, and on ART but non-suppressed sub-groups. Across surveys, undiagnosed and diagnosed but untreated contributed most to transmission (40–91% and 1–41%, respectively), with less than 1% from those with LLV. Between 2010 and 2020, the proportion of transmission from individuals on ART but non-suppressed increased. In settings with high ART coverage, effective HIV testing, ART linkage, and retention remain priorities to reduce HIV transmission. Persons with LLV are an increasing share of PLHIV but their contribution to HIV transmission was small. Improving suppression among PLHIV on ART with VL ≥1000 copies/mL will become increasingly important.