The epidemiology of HIV population viral load in twelve sub-Saharan African countries
Authors: Hladik Wolfgang , Stupp Paul , McCracken Stephen D. , Justman Jessica , Ndongmo Clement , Shang Judith , Dokubo Emily K. , Gummerson Elizabeth , Koui Isabelle , Bodika Stephane , Lobognon Roger , Brou Hermann , Ryan Caroline , Brown Kristin , Nuwagaba-Biribonwoha Harriet , Kingwara Leonard , Young Peter , Bronson Megan , Chege Duncan , Malewo Optatus , Mengistu Yohannes , Koen Frederix , Jahn Andreas , Auld Andrew , Jonnalagadda Sasi , Radin Elizabeth , Hamunime Ndapewa , Williams Daniel B. , Kayirangwa Eugenie , Mugisha Veronicah , Mdodo Rennatus , Delgado Stephen , Kirungi Wilford , Nelson Lisa , West Christine , Biraro Samuel , Dzekedzeke Kumbutso , Barradas Danielle , Mugurungi Owen , Balachandra Shirish , Kilmarx Peter H. , Musuka Godfrey , Patel Hetal , Parekh Bharat , Sleeman Katrina , Domaoal Robert A. , Rutherford George , Motsoane Tsietso , Bissek Anne-Cécile Zoung-Kanyi , Farahani Mansoor , Voetsch Andrew C. 
Published: June 2023

Background
We examined the epidemiology and transmission potential of HIV population viral load (VL) in 12 sub-Saharan African countries.

Methods
We analyzed data from Population-based HIV Impact Assessments (PHIAs), large national household-based surveys conducted between 2015 and 2019 in Cameroon, Cote d’Ivoire, Eswatini, Kenya, Lesotho, Malawi, Namibia, Rwanda, Tanzania, Uganda, Zambia, and Zimbabwe. Blood-based biomarkers included HIV serology, recency of HIV infection, and VL. We estimated the number of people living with HIV (PLHIV) with suppressed viral load (<1,000 HIV-1 RNA copies/mL) and with unsuppressed viral load (viremic), the prevalence of unsuppressed HIV (population viremia), sex-specific HIV transmission ratios (number female incident HIV-1 infections/number unsuppressed male PLHIV per 100 persons-years [PY] and vice versa) and examined correlations between a variety of VL metrics and incident HIV. Country sample sizes ranged from 10,016 (Eswatini) to 30,637 (Rwanda); estimates were weighted and restricted to participants 15 years and older.

Results
The proportion of female PLHIV with viral suppression was higher than that among males in all countries, however, the number of unsuppressed females outnumbered that of unsuppressed males in all countries due to higher overall female HIV prevalence, with ratios ranging from 1.08 to 2.10 (median: 1.43). The spatial distribution of HIV seroprevalence, viremia prevalence, and number of unsuppressed adults often differed substantially within the same countries. The 1% and 5% of PLHIV with the highest VL on average accounted for 34% and 66%, respectively, of countries’ total VL. HIV transmission ratios varied widely across countries and were higher for male-to-female (range: 2.3–28.3/100 PY) than for female-to-male transmission (range: 1.5–10.6/100 PY). In all countries mean log10 VL among unsuppressed males was higher than that among females. Correlations between VL measures and incident HIV varied, were weaker for VL metrics among females compared to males and were strongest for the number of unsuppressed PLHIV per 100 HIV-negative adults (R2 = 0.92).

Conclusions
Despite higher proportions of viral suppression, female unsuppressed PLHIV outnumbered males in all countries examined. Unsuppressed male PLHIV have consistently higher VL and a higher risk of transmitting HIV than females. Just 5% of PLHIV account for almost two-thirds of countries’ total VL. Population-level VL metrics help monitor the epidemic and highlight key programmatic gaps in these African countries.