Hermans HE, et al. - For low-income and middle-income countries, WHO guidelines define failure of Antiretroviral therapy (ART) with a lenient threshold of viraemia (HIV RNA viral load ≥1000 copies per mL). In a large South African cohort, researchers examined the occurrence of detectable viraemia during ART below this threshold and its effect on treatment outcomes. Findings revealed a frequent occurrence of low-level viraemia in this cohort. This increased the risk of virological failure and switch to second-line ART. To meet UNAIDS-defined targets aimed at halting the global HIV epidemic, strategies for management of low-level viraemia need to be incorporated into WHO guidelines.