Viral suppression reduces HIV risk despite more sex and 'condom fatigue' in patients starting treatment in Cameroon

Concerns that HIV treatment may lead to increased rates of unprotected sex and a decline in condom use need to be considered in the context of the very substantial reduction in the risk of HIV transmission when viral load is fully suppressed, researchers from Cameroon reported on Monday at the Sixth International AIDS Society conference (IAS 2011) in Rome.

Results from a study of patients starting antiretroviral therapy in rural hospitals in Cameroon (Cohen) indicate that, while sexual activity increased after the initiation of treatment, and unprotected sex reverted back to baseline after an initial decline, the increase in the proportion of patients with undetectable HIV, and therefore much less infectious, more than compensated for an increase in otherwise risky behaviour.

The other significant finding in the study was that patients who reported poor communication with their healthcare staff were nearly twice as likely to report not always using condoms while having a detectable HIV viral load, though whether this is cause or effect cannot be shown.

The Stratall ANRS 12110/ESTHER study was a French study of 459 patients, 70 of them women, initiating antiretroviral therapy (ART) in rural hospitals in Cameroon. Its primary aim was to compare clinical outcomes in people randomised either to receive clinical care based on symptoms alone or on symptoms plus laboratory monitoring. Results announced at this year’s Conference on Retroviruses and Opportunistic Infections (Kouanfack) indicated a slight, but significant advantage for laboratory monitoring – see this report for more details.    

An important aspect of the Stratall ANRS 12110/ESTHER trial was that sexual behaviour in participants was assessed too. Previously, there have been relatively few studies of the effect of initiating HIV therapy on sexual and risk behaviour of patients in developing countries.

A paper presented at the International AIDS Conference in Vienna last year (Marcellin) found that the proportion of trial participants having sex did increase after the initiation of ART, as did sex with serodiscordant partners. In this study, sexual behaviour data was collected from 447 of the participants. They found that the proportion of patients reporting sex doubled over the two years of the study from 32% at the start of therapy to 60% two years later. The proportion of participants who had sex involving inconsistent condom use (ICU) with partners not known to be HIV-positive (SD-ICU) was 57% in participants who had not been having sex at baseline and 76% in participants who had.    

This raised concerns about the potential for increased access to HIV treatment to restart high rates of HIV transmission. However, this paper did not factor in the reduced infectiousness of patients with viral suppression.

The paper presented this year added to this data. It measured sexual behaviour only in patients where full data from every visit both on sexual behaviour and viral load were available, a total of 290 patients.

It found that about a third of patients at any one time had a detectable viral load (over 40 copies/ml), with this proportion declining slightly from 37% six months after therapy initiation to 32% two years after.

In common with the Vienna study, it found that the proportion of patients admitting to no or inconsistent condom use (ICU) declined after initiation of therapy from 67% at baseline to 40% at month six but then started increasing again, to 55% at month 24.

However, due to the effects of treatment, the proportion of patients who were defined as ‘susceptible to transmitting HIV’ (STH), in other words using condoms inconsistently while not being virally suppressed, remained steady through the study. While 64% of patients at baseline were in this group, only 23% were at month six and 22% at month 24. Increased levels of sexual activity were therefore balanced out by an increased rate of viral suppression.

The investigators found that treatment reduced an individual’s susceptibility to transmitting HIV by 86% at month six and 89% at month 24.

Other factors related to being ‘STH’ included having more than one sexual partner (2.4 times the risk of being STH) and having sex more than once a week (twice the risk). Another risk factor was ‘limited readiness of health staff to listen’. All of these factors were statistically significant.

The last factor was assessed using a six-point multiple-choice patient questionnaire that asked patients to rate the quality of their relationship with healthcare providers; those rating the poorest quality of communication with healthcare staff were 80% more likely to report susceptibility to transmitting HIV, though from this trial it cannot be shown whether poor communication was responsible for sexual risk or both were symptomatic of underlying factors like depression.