HIV-positive people on antiretroviral (ARV) treatment tend to overestimate their chances of passing the virus on to others, despite research suggesting that having an undetectable viral load makes transmitting HIV highly unlikely, if not impossible. Researchers followed 1,809 treatment-naive people living with HIV who were participating in a randomized open-label study of ARV treatment. The follow-up period lasted up to 192 weeks.

Raphael J. Landovitz, MD, MSc, an associate professor of medicine at the University of California, Los Angeles (UCLA) Center for Clinical AIDS Research and Education and the study’s lead, presented findings at the 2016 Conference on Retroviruses and Opportunistic Infections (CROI) in Boston.

The researchers asked the participants to rate their level of infectiousness on a 0 to 100 scale, which the investigators divided into four categories: high (67 to 100), medium (34 to 66), low (1 to 33) and not infectious (zero).

Before starting HIV treatment, a respective 58 percent, 26 percent, 10 percent and 6 percent of participants perceived themselves to be of high, medium, low, and non-existent infectiousness. After 48 weeks of treatment, these proportions shifted to 38 percent, 20 percent, 32 percent and 10 percent. At this point, 91 percent of the participants had a fully suppressed virus.

Forty-nine percent of the participants reported a reduction in their perceived infectiousness between the study’s outset and week 48 of treatment.

Those who were younger and more educated were more likely to report a reduction in their perceived infectiousness. Those who were black or who had fewer than 50 CD4s at the beginning of the study were less likely to report such reduction.

Just 99 people perceived themselves as non-infectious, among whom eight had a detectable viral load. Factors associated with participants’ shifting to thinking of themselves as non-infectious during the study included starting with lower perceived infectiousness, being female and not taking stimulant drugs.

Interestingly, there was no apparent association between participants’ viral suppression and their perception of their infectiousness.