Implication of the elusive undetectable viral load

I have been party to a couple of discussion recently where there has been conjecture about the implications of an elusive undetectable viral load. Before I am attacked as a naysayer, I am not suggesting that total viral suppression is not the aim of antiviral therapy. It is and always has been. But some attention is now being directed at transient, persistent and recurrent low-level viral load. Along with virological and clinical implications, this may also have social and emotional costs for people living with HIV.

Some patients, particularly those who have been significantly pre-treated, no matter how compliant, do not achieve complete viral suppression. Others experience intermittent blips or periods of viraemia. What are the implications of these events? It is important to understand this as fully as we can because we must give people living with HIV reasoned and reasonable information; it fundamentally underpins the thinking behind approaches to cure research and, from a public health and prevention perspective, we must be careful not to alienate people.

Poster 136 (Silva, J. et.al.) from Portugal, present a retrospective observational analysis of low-level viraemia and its immunological and virological significance. It was a relatively large study of 2,161 patients 93% on ART 19% had low level viraemia 52% of whom were adherent. The mean VL was 46 (21 - 190) with an average CD4 of 665 (126 - 2,393). There was no documented virological failure, yet 51% had transient viraemia defined as one detectable VL in the study period, 40% had persistent (constantly detectable) virus and 9% had intermittent (2 occasions of detectable VL with undetectable VL in between).

Their conclusion was "in the absence of significant differences in immunological and virological outcomes and the absence of virological failure, suggests a scarce impact of low level viraemia in patient prognosis." This is qualified by suggesting that prospective and more accurate data are required. A number of oral presentations recommended treatment adherence counselling, rather than automatic switching in the presence of low level viraemia.