A meta-analysis of every study that has looked at the sexual behaviour of people after starting HIV treatment has found not a single instance
of so-called ‘risk compensation’ – the idea that if people start taking HIV
treatment they will fear transmitting HIV less and so start taking more risks.
On the contrary: in 15 studies that met inclusion criteria for
the analysis, starting HIV treatment was consistently associated with a fall in
sexual risk behaviour, as measured by increased condom use. This association
held true for both genders; for committed relationships and casual sex; and for
partners both known, and not known, to be HIV negative.
The results were presented at the 20th International AIDS Conference (AIDS 2014) in Melbourne, Australia.
The limitations of this meta-analysis are that most of the
studies were conducted in sub-Saharan Africa and among heterosexual people, so the
results might not hold for other areas and for other populations such as gay
men. But the meta-analysis does appear to demolish the idea that riskier behaviour
is an inevitable, or even a normal, reaction to taking HIV treatment.
The Evidence Project is a programme sponsored by the US
National Institute of Mental Health examining the strength of evidence for different
behavioural interventions in people living with HIV. Researchers from Johns Hopkins and South
Carolina Universities in the US combed through the literature to find studies
published between 1990 and May 2012 that were conducted in low- or middle-income
countries, provided treatment and, when it became available, combination antiretroviral
therapy (ART) to people living with HIV; and which compared sexual risk behaviour either
in people on ART with people not on ART, or in the same people before and after
They found 37 studies that met these criteria (and another twelve
only conducted in high-income countries). Thirty of the 37 came from
sub-Saharan Africa, four from Thailand, two from Brazil and one from India.
Sexual risk was defined in a number of different ways including
condom use, number of partners, proportion having casual sex, proportion abstinent,
time of sexual debut, and incidence of sexually transmitted infections (STIs). For the
sake of consistency, therefore, the current analysis only looked at 15 studies
that rated the most commonly measured risk behaviour, condom use.
Overall, for both genders and any type of partner, the studies
found that people taking ART used condoms 80% more often than people not on ART.
In women on ART, rates of condom use doubled compared with women not on ART, and in
men on ART, condom use was 50% higher. The association was even stronger when
restricted to particular kinds of partner: the four studies that looked specifically
at sex with partners of opposite or unknown HIV status found that condom use in
people on ART rose by 160%, and it also rose by 160% (albeit from a much lower
level) with spouses or regular partners.
These figures were for consistent condom use. The study found
that the figures also held when condom use at last sex was considered. Overall,
condom use at last sex was 130% higher in people on ART. It was also 110%
higher in women specifically, 40% higher in men and 120% higher in people of
negative or unknown HIV status, but in these three cases, the association was
not statistically significant.
As well as holding true across groups, the association also held
true over time: people on HIV treatment were more likely to use condoms from the
earliest trial of HIV drugs in 1990 to the latest trial of ART in 2012. The majority
of studies in fact came from the last decade, and the number of studies relating
ART to sexual risk behaviour has increased exponentially recently: a new search has found 50 studies in the last
two years that meet the inclusion criteria. This should enable new analyses to
be made of other risk factors such as number of partners and of
non-self-reported outcomes such as STI incidence.
The meta-analysis was restricted to
heterosexual people and to low- and middle-income countries. But the consistency of its findings
“This is encouraging news for the continued expansion of ART
in low- and middle-income countries”, said presenter Caitlin Kennedy. She
suggested that instead of ‘treatment optimism’ causing complacency, the
provision of ART could lead to decreased HIV risk behaviour partly due to regular
medical contact and counselling, and partly due to an increased hope for the future
and sense of agency.
“They suggest that the phrase ‘treatment is prevention’ may be
true in more ways than one,” she added.