HIV Virological failure among patients with persistent low-level viremia:  Is it time to change the WHO >1000 virologic failure threshold?

Virological failure is an important determinant of treatment outcome among HIV positive patients. The significance of Persistent Low-Level Viremia (PLLV) on virological failure is a current area of interest in HIV management.  Kenyan researchers namely Prof Nancy Budambula of University of Embu (UoEm), Ms Mirriam Nzivo (JKUAT), Dr Cecilia Waruhiu (TAGCC) and Mr James Kangethe (KNH) have called for the revision of the >1000 copies/ml threshold that is too lenient to >200copies/ml.

The researchers examined records of over 10,000 HIV positive patients enrolled at the Comprehensive Care Centre (CCC) of the Kenyatta National Hospital.  They sought to establish the significance of PLLV on virological failure and determined that PLLV of 200-999 copies/ml was a risk factor for virological failure. They also observed that among patients experiencing PLLV, adolescents, young adults and patients who switched from first line to second line regimen were at higher risk of virological failure. According to Kenya’s National AIDS and STD Control Programme (NASCOP), PLLV among HIV patients is defined as having detectable viral load above the lower detection limit value but less than a 1,000 copies/ml on at least two consecutive measures. Kenya and other developing countries follow the World Health Organization (WHO) guidelines of the >1000 copies/ml threshold unlike some developed countries which have adopted different guidelines regarding virological failure. The European AIDS Clinical Society 2020 Guidelines define virological failure as viral loads ≥50 copies/ml while the Department of Health and Human Services in United States of America defines virological failure as detectable viremia ≥200 copies/ml.  From the findings of this study and other accumulating evidence, the >1000 copies/ml threshold is too lenient and should be reviewed to at least >200copies/ml. This would ensure frequent monitoring of viral load, drug resistant mutants and adherence among others in patients who persistently have viral loads >200copies/ml.

This work has been published in BioMed Research International under the title “HIV virologic failure among patients with persistent low-level viremia in Nairobi, Kenya: It is time to review the >1000 virologic failure threshold”.  For more details read the full article at