Page 30 - Nursing Matters June 2021 Vol 12

Viral load and resistance:

updates from the Southern

African HIV Clinicians’ Society

Adult ART 2020 Guidelines

Jeremy Nel, MBChB, FCP(SA), Cert ID(SA), DTM&H
Division of Infectious Diseases, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg

The viral load remains the best way When should subsequent viral recommended that 2 consecutive viral
of monitoring patients who are on loads be checked? loads >50 copies/mL, taken 2-3 months
antiretroviral therapy (ART) and apart, is a more appropriate definition of
outperforms both the CD4 count and Assuming the patient’s viral load remains virological failure. However, guidelines
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a clinical assessment when it comes suppressed, repeat viral load testing from the South African National
to determining early treatment failure. 1 is recommended at months 3, 6, and Department of Health and the World
The following questions reflect the latest 12 on ART, then every 6-12 months Health Organization still recommend a
advice from the Southern African HIV thereafter. Patients whose viral loads viral load threshold of 1000 copies/mL.
Clinicians’ Society (SAHCS) Adult ART remain suppressed up until 12 months,
2020 guidelines. and who demonstrate that they have What is a viral blip?
been taking their medication regularly
What is the role of a baseline and reliably, can probably be followed A viral blip is a low level (<1000
viral load? up with an annual viral load thereafter copies/mL) episode of HIV viraemia
(Figure 1). that is not sustained – i.e. the viral load
The Southern African HIV Clinicians’ measurement following the blip returns
Society still recommends a baseline viral What is the definition of to a level <50 copies/mL. The causes
load for patients newly initiated on ART. virological failure? of viral blips are not completely known,
The reasons for this are three-fold. Firstly, but probably include a recent episode
this allows for clinicians to interpret a The SA HIV Clinicians’ Society Adult of immune activation (such as following
repeat viral load done 3 months later, at ART 2020 guidelines have made an an acute infection), and recent non-
which time point the viral load should be important change to the definition adherence.
1/100th (at least a 2 log drop) or less of virological failure (VF). Whereas
of the baseline viral load. Secondly, it is previous guidelines had used a threshold What are the possible reasons
important because rilpivirine is relatively of 1000 copies/mL to define VF, there is for virological failure?
contraindicated if the baseline viral load now good evidence that sustained viral
is more than 100,000 copies/mL, as loads at levels of anything more than In theory, virological failure can occur
at these high levels rilpivirine has been 50 copies/mL cause the accumulation for only one of three reasons:
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associated with decreased efficacy. of resistance mutations, and ultimately 1. The patient isn’t taking their
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Lastly, a viral load can also act as a lead to virological failure. The Adult medication (non-adherence)
confirmatory test for HIV itself. guidelines committee therefore 2. There is significant drug resistance
HIV Nursing Matters | June 2021 | page 28