The importance of routine viral load monitoring: Higher levels of resistance at antiretroviral therapy failure in Uganda and Lesotho compared to Switzerland. Journal of Antimicrobial Chemotherapy
Bachmann et al. aimed to assess genotypic resistance patterns in two Sub-Saharan African cohorts (Uganda and Lesotho) compared to a sub-cohort of the Swiss HIV Cohort Study (SHCS).
The Sub-Saharan cohorts included individuals prior to access to routine viral load (VL) monitoring who had virological failure while taking first-line NNRTI-containing antiretroviral therapy (ART). The SHCS sub-cohort included individuals taking NNRTI-based ART who had regular routine VL monitoring and a first-time genotypic resistance test (GRT) upon presentation with VL ≥1000 copies/mL.
The authors found that 50.8% of individuals in the SHCS, 72.5% in Uganda and 81.0% in Lesotho harbored HIV with high-level resistance to at least two drugs from their current regimen. Stanford resistance scores were higher in Uganda compared with Switzerland for all drugs used in first-line treatment except zidovudine and tenofovir (P<0.01) and higher in Lesotho compared with Uganda for all drugs used in first-line treatment except zidovudine (P<0.01).
In conclusion, frequent VL monitoring and possibly pretreatment GRT as done in the SHCS pays off by low levels of resistance even when treatment failure occurs. The high number of individuals among the Sub-Saharan cohorts with resistance to their current ART regimens is a serious public health concern that will not be reversed with the introduction of dolutegravir in Sub-Saharan Africa, as dolutegravir will also be prescribed with an NRTI backbone. Hence, the study-results highlight the importance of further upscaling virological monitoring in resource-limited settings.