Background
Viral suppression estimates are essential for monitoring progress towards the UNAIDS 95-95-95 targets. We sought to generate updated estimates of viral suppression rates in South African adults on antiretroviral treatment (ART) to understand changes in viral suppression following the introduction of dolutegravir and the COVID-19 epidemic.
Methods
This retrospective cohort study included adults (15 years or older) starting ART between 2005 and 2023 from seven South African sites of the International epidemiology Databases to Evaluate AIDS collaboration. We excluded those with no recorded baseline CD4 count or who were virologically suppressed before starting ART. Participants were censored at the earliest of death, transfer to another facility, 180 days after the last recorded visit (“lost to follow-up”), or 31 December 2023. After starting ART, viral load testing was scheduled at 6 months, 1 year, and yearly thereafter. Missing viral loads were imputed using multivariate imputation by chained equations. Viral suppression was defined as less than 1000 copies/ml. Multivariable logistic regression was used to estimate associations with viral suppression.
Results
187 624 participants contributed 986 348 person-years of observation. The proportion virologically suppressed reached a low of 86.4% in the 2011 calendar year, and then increased steadily to 94.8% in 2022. Virological failure was less likely amongst those starting ART on dolutegravir-based regimens than those starting on other regimens (adjusted odds ratio [aOR] 0.45, 95% CI 0.42-0.50). The odds of virological failure was lower amongst females (aOR 0.80, 95% CI 0.78-0.82), and decreased with increasing baseline CD4 count, duration on ART, and age (Figure 1). The odds of virological failure during the height of the COVID-19 pandemic (2020-2021) did not differ from other years (aOR 1.03, 95% CI 0.99-1.07). Those with a history of previous care interruptions, defined as gaps in contact longer than 180 days, were more likely to be virally unsuppressed (aOR 1.88, 95% CI 1.82-1.95).
Conclusions
Viral suppression rates in South Africa are on a promising trajectory toward the 95% UNAIDS target. The introduction of dolutegravir has likely contributed positively to the ongoing success of the national HIV programme. Viral suppression was not adversely affected by the COVID-19 pandemic, highlighting the resilience of the health system.
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