Epidemiological trends of HIV among individuals aged 15-54 years in South Africa from 2004 to 2025: a population-based, longitudinal cohort study

Why clinicians should know about it

• Picked for Epidemiology (top studies of the week, 11 October 2026): Population‑based longitudinal HIV cohort from 2003‑2025

Abstract

BACKGROUND: South Africa has mounted the largest HIV prevention and treatment programme in history, delivering substantial gains in survival and prevention of new HIV infections; however, service disruptions and recent funding losses might jeopardise these successes. There is a scarcity of high-quality, population-based empirical evidence on key epidemic metrics needed to accurately gauge recent progress towards epidemic control in South Africa. We aimed to evaluate recent progress towards HIV epidemic control in South Africa by quantifying long-term trends in key epidemic control metrics in a large population-based cohort in rural KwaZulu-Natal, South Africa. METHODS: In this population-based, longitudinal cohort study, we used prospectively collected HIV testing, sociodemographic, behavioural, and population viral load data from the Africa Health Research Institute (AHRI) health and demographic surveillance system in rural KwaZulu-Natal from 2003 to 2025. Population-based HIV surveys (encompassing individual health interview and HIV testing) take place annually in all consenting resident individuals aged 15 years or older. We used Poisson regression models to quantify trends in directly observed HIV incidence in repeat testers (aged 15-54 years) who had initially tested negative for HIV and subsequently received at least one valid HIV test result. We further analysed 11 rounds of population viral load testing conducted between 2011 and 2025. We used generalised estimating equations to quantify population viral suppression metrics and calculated trends in the incidence-to-prevalence ratio, a key metric for evaluating progress towards epidemic control. FINDINGS: Between June 24, 2003, and May 22, 2025, across the population cohort, 59 806 (65·4%) of 91 367 contacted individuals aged 15-54 years consented to participate at least once in population-based HIV testing. Of those tested, 33 754 (56·4%) were female and 26 052 (43·6%) were male, with a median age of 26·7 years (IQR 19·3-39·1) at testing date. Among 42 662 participants who initially tested HIV negative and were recontacted, 29 702 (69·6%) underwent repeat HIV testing and were included in the incidence analysis. In this group, over 182 112 person-years of observation, we observed 4852 HIV seroconversions. From 2013 to 2018, overall annual HIV incidence rates declined by 52·2% in males and 36·9% in females. We found no evidence of a continued downward trend in HIV incidence between 2019 and 2025 among either females or males. After a period of substantial decline (from 2011 to 2018), population detectable viraemia increased significantly from 2019 to 2025 by 9·6 percentage points (95% CI 5·4-13·8), remaining an estimated 30·7 percentage points (95% CI 27·2-34·3) below the UNAIDS 95-95-95 population viral suppression target. The incidence-to-prevalence ratio decreased substantially across consecutive survey rounds, from 0·132 (95% CI 0·114-0·152) in 2006 to its lowest recorded value of 0·034 (95% CI 0·028-0·042) in 2022, representing an overall 74·2% decline. After 2022, the ratio stagnated above the epidemic control benchmark of 0·03. INTERPRETATION: These epidemic metrics show that progress towards HIV epidemic control is faltering in KwaZulu-Natal, South Africa. The tools to reverse this trajectory are available; the challenge now is to ensure their sustained and effective implementation through coordinated action across research, policy, government, civil society, and international funding partners. We can, and we should, change course now if we want to achieve an AIDS-free generation in South Africa and the world. FUNDING: National Institute of Mental Health and Wellcome Trust.

Abstract as published, via PubMed.