The first national analysis of repeat viral load testing in South Africa finds that 85% of people on HIV treatment, with increasing viral loads, received further monitoring – but only half did so within the recommended time.
The World Health Organisation (WHO) recommends viral load monitoring for people on antiretroviral treatment (ART) to determine whether someone’s treatment is succeeding or failing and whether a change in ART regimen is needed. If unaddressed, treatment failure leads to poor health for the individual and increases the risk of onward transmission.
Until 2019, HIV treatment guidelines in South Africa recommended repeat viral load testing within six months if someone’s viral load increased to between 400 and 1,000 copies/mL, and within two to three months if someone’s viral load went above 1,000 copies/mL.
To examine whether these targets are being met, researchers analysed national data relating to 3.5m adults living with HIV on ART who had a viral load test between 2004 and 2014. They found that just over 371,500 people went from being virally suppressed to having an increased viral load of at least 400 copies/mL. Of these, 84% received an additional viral load test within 24 months.
Around 56% of those with an increased viral load between 400 and 1,000 copies/mL had a repeat viral load test within the recommended six months. But the median waiting time for this group was 7.5 months – 1.5 months longer than recommended. Among those with an increased viral load above 1,000 copies/mL, 48% had an additional viral load test within the recommended time of two to three months. For this group, the median waiting time was 6.2 months – around double the recommended time.
Although the waiting time targets were missed overall, some individual provinces such as the Western Cape did meet national guidance. Others, such as Mpumalanga province, fared even worse than the national average at a waiting time of eight months.
The study found the waiting time to receive repeat viral load testing increased year on year from 2005 until 2012 when it levelled off. The proportion of people receiving a repeat viral load test within recommended times declined from 77% in 2005 to 45% in 2014. The authors note that this is to be expected as it reflects the increasing number of people in South Africa on ART in the past two decades.
The study found a small increase in repeat testing associated with higher viral load and very low CD4 counts at first increased viral load test. Being younger (under 25) was also associated with having to wait a longer time for repeat testing.
The reasons for delays in repeat testing were not examined by the study and more work is needed to understand what causes these delays in order to reduce them. Given the variation in waiting times between provinces, these efforts may need to focus on areas with the longest delays to make the most impact.
In 2019, South Africa changed its viral load monitoring guidelines. Now anyone with a viral load higher than 50 copies/mL is required to return for viral load testing after three months. It remains unclear what impact this will have on repeat testing. But given the current limitations on repeat testing at three months for those with high viral loads, monitoring patterns of repeat testing will be important for improving the health of people living with HIV whose treatment is beginning to fail.
Introduction: In South Africa, HIV patients with an elevated viral load (VL) should receive repeat VL testing after adherence counselling. We set out to use a national HIV Cohort to describe time to repeat viral load testing across South Africa and identify predictors of time to repeat testing.
Methods: We conducted a cohort study of prospectively collected laboratory data. HIV treatment guidelines have changed over time in South Africa, but call for repeat VL testing within six months if 400 to 1000 copies/mL and two to three months if >1000 copies/mL. We included patients with suppressed viral loads (indicating they are on ART) and a first elevated VL (>400 copies/mL) between April 2004 and December 2014. Follow‐up began at first elevated VL and continued until repeat testing, loss to follow‐up or December 2016. We calculated adjusted hazard ratios (aHR) using Cox proportional hazard models.
Results: Of 371,648 patients with a VL > 400, 83.9% (311,790) had a repeat VL, in a median (IQR) of 7.0 (4.1 to 12.2) months. Of those with a first viral load 400 to 1000 copies/mL, 56.4% had a repeat VL within guideline recommended six months (defined as up to nine months), whereas among those >1000 copies/mL only 47.7% had a repeat viral load within guideline recommended two to three months (defined as up to six months). We found a small increase in repeat testing associated with higher VL value (aHR 1.11; 95% CI: 1.10 to 1.12 comparing >1000 vs 400 to 1000 copies/mL) and very low CD4 counts at first elevated VL (aHR 1.16; 95% CI: 1.13 to 1.19 comparing CD4 < 50 vs <500 cells/mm3). We also found strong variation in time to repeat VL testing by province.
Conclusions: Median time to repeat viral load testing for those with an elevated viral load was longer than guidelines recommend. Future work should identify whether delays are due to patient or provider factors.
Matthew P Fox, Alana T Brennan, Cornelius Nattey, William B MacLeod, Alyssa Harlow, Koleka Mlisana, Mhairi Maskew, Sergio Carmona, Jacob Bor
Journal of the International Aids Society abstract