HIV-positive people taking antiretrovirals who have an ongoing detectable viral load may be at a raised risk for treatment failure even when the levels are as low as 50 to 199. U.S. treatment guidelines state that there is no evidence that this viral load range poses such a risk. But a recent Canadian study found that the 50 to 199 window slightly more than doubles the risk of treatment failure when compared with undetectable viral loads. (Standard viral load tests cannot detect levels below 50.)

Claudie Laprise, PhD, a postdoctoral fellow in the division of cancer epidemiology at McGill University in Montreal, who led the study while at the Université de Montréal, says that much more research is needed to confirm her findings. And while acknowledging that “there are a lot of clinical factors to consider before changing” HIV medications, she says that physicians should still consider low-level viral replication as part of the overall risk of potential treatment failure and include the factor in their clinical decision making.