Viral Load Testing—Should It Be the Standard of Care in Asia?

March  2011—An ongoing global debate is weighing whether HIV treatment can be monitored successfully by clinical assessments and CD4 testing alone, or if more sensitive—and more expensive—viral load tests should be considered the standard of care, even in resource-limited countries. The crux of the debate is whether virologic monitoring (using viral load testing) can prevent unnecessary switches to second-line antiretroviral therapy (ART) by allowing clinicians to more reliably identify treatment failure, and whether it can be implemented in an economically feasible way. Answers to these questions would allow ART to be more proactively managed to delay disease progression and drug resistance.

 In a recent study in India, 122 adults were referred for viral load testing when they were found to be failing first-line ART following the clinical and CD4-based criteria recommended by the World Health Organization (WHO). Researchers found that 24 percent of patients who ordinarily would have been switched to second-line ART using these criteria actually had undetectable viral loads, representing very low levels of active HIV virus in the body. This showed that their ART was working to control their HIV infection. The researchers concluded that using viral load testing to evaluate treatment failure could prevent unnecessary switches to second-line ART.¹ 

The benefit of viral load monitoring has been shown in children as well. In another study of 584 HIV-positive children in Latin America, a viral load of more than 5,000 copies/mL was found to reliably predict which children would go on to worsening HIV disease.² The lack of routine viral load testing was felt to delay recognition of treatment failure until after significant clinical illness and even drug resistance occurred. The researchers commented that having a viral load test done twice a year could lead to better treatment outcomes by identifying children and families who may be in need of greater adherence support or second-line ART.

While viral load testing is part of standard practice in high-income countries, it is considered too expensive and technically challenging for many HIV clinics in resource-limited settings, including in Asia. A recent TREAT Asia study sought to explore how the availability of clinical resources influences treatment outcomes. Data from 2,333 adults in this regional cohort showed a 35 percent increase in disease progression among patients receiving viral load testing less than once per year, compared to patients who had more frequent testing^.3 The researchers commented that the lack of viral load testing also put patients at risk of developing drug resistance during periods of failure.

All three studies encourage the adoption of routine viral load testing as the standard of care in resource-limited settings.

1 Rewari BB, et al. Evaluating patients for second-line antiretroviral therapy in India: The role of targeted viral load testing. J Acquir Immune Defic Syndr. 2010 Oct 1. [Epub ahead of print]

2 Oliveira R, et al. Viral load predicts new World Health Organization Stage 3 and 4 events in HIV-infected children receiving highly active antiretroviral therapy, independent of CD4 T lymphocyte value. CID. 2010 Dec 1;51(11):1325-33. [Epub 2010 Nov 1]

 3 Oyomopito R, et al. Measures of site resourcing predict virologic suppression, immunologic response and HIV disease progression following highly active antiretroviral therapy (HAART) in the TREAT Asia HIV Observational Database (TAHOD). HIV Medicine. 2010. [Epub ahead of print]