HIV-positive people on antiretrovirals (ARVs) who have a persistently detectable viral load are at an increased risk for treatment failure, even when the levels are as low as 50 to 199, aidsmap reports. Publishing their findings in the online edition of Clinical Infectious Diseases, Canadian researchers studied 1,357 people treated for HIV in Montreal, beginning in 1999. The participants were required to take ARVs for 12 months; the follow-up period extended as long as 12 years.

U.S. treatment guidelines state that there is no evidence that viral loads below 200 increase the risk for treatment failure, which is also known as virologic failure. Contrasting this, the study authors state that even detectable viral loads in this low range (a viral load is detectable at 50 or above) should prompt clinicians to “act aggressively,” addressing adherence issues, drug dosage, drug interactions, genotype testing and conducting other forms of closer monitoring.

Among the study participants who maintained an undetectable viral load, only 7 percent experienced treatment failure, defined as a viral load rising above 1,000. Out of those who had a persistent viral load between 50 and 199, 23 percent failed treatment. Those with a viral load between 200 and 499 failed at a rate of 24 percent, and those with a viral load between 500 and 999 failed at a rate of 59 percent.

After controlling for various factors, the researchers concluded that having a persistent viral load between 50 and 199 or between 200 and 499 slightly more than doubled the risk of treatment failure; and those with a persistent viral load between 500 and 999 have a nearly fivefold increased risk.

To read the aidsmap story, click here.

To read the study abstract, click here.