It is now well-established that people with HIV on treatment with an undetectable viral load are not infectious. Nonetheless, a significant proportion of patients taking long-term HIV therapy over-estimate their risks of infecting a partner, according to new US research.

The study involved 1809 people with HIV who were monitored for three years after starting treatment. The findings showed there was no correlation between an individual’s actual viral load and estimates of their infectiousness.

Patients were asked at the start of the study and then each year to rank their potential infectiousness.

Average viral load before starting therapy was 40,000 copies/ml and in a third of patients it was over 100,000 copies/ml. At this point, 58% rated their potential infectiousness as high and 26% as medium. At the three-year follow-up point, almost all the patients – 90% – had a sustained undetectable viral load. However, 36% rated their infectiousness as high, a fifth as medium and only 14% considered themselves non-infectious.

The full article can be read here.