Over the last five years, half of the gay men diagnosed with HIV in France acquired their infection in the six months before diagnosis, researchers report in the 3 December issue of Eurosurveillance. This suggests that HIV incidence (the rate of new infections) is extremely high in this population. However it may also point to high rates of testing among some groups of gay men.
After many years in which only AIDS diagnoses had to be reported, the French public health reporting system has been considerably strengthened in recent years. Since 2003, reporting of HIV diagnosis has been mandatory. Moreover, a test to identify recent infections is routinely recommended, as long as the individual gives consent.
The test for recent infection is one of a number of techniques sometimes referred to as STARHS or incidence tests which look for specific antibody markers that give different results in the months following infection. If a test gives a result below a pre-determined cut-off point, it is deemed to be a recent infection.
Each year, around 6,500 - 7,500 people are newly diagnosed with HIV in France. The numbers of gay men (and other men who have sex with men) diagnosed has increased from below 2,000 in 2003 to around 2,500 for each of the last three years.
Epidemiologists analysed the available data on gay men diagnosed between 2003 and 2008, although quite a lot of information is missing. Clinicians had failed to supply information on mode of transmission for 31% of individuals who were diagnosed, and recent infection results were only available for 4,819 gay men.
The average age for gay men diagnosed was 37. Independently of the test for recent infection results, 19% of diagnosed gay men were thought by their clinician to be diagnosed during primary infection.
Moreover, the test for recent infection showed that 48% of men had been infected in the previous six months. This figure remained stable between 2003 and 2008.
Men who had taken at least three HIV tests in their life were four times more likely to be diagnosed with recent infection than men who were diagnosed on their first HIV test. Being diagnosed in recent infection was more common both for men with French nationality and those with higher socio-economic status.
Moreover, recent infection was more common for younger men, with 57% of those diagnosed aged 15-29 having recent infection, compared to 30% of men aged 50 and over. In line with this, whereas 11% of all gay men were diagnosed very late (with an AIDS-defining illness) this figure rose to 27% for those men aged over 50. The numbers of men diagnosed late declined during the study period.
Older men were more likely to take a test because of symptoms, whereas younger men tended to do because of their risk behaviour.
The authors note that the high number of recent infections in gay men probably reflects both testing behaviour and HIV incidence. They plan to publish a study estimating incidence rates in 2010.
Describing their data as worrying, they comment: “Prevention campaigns remain crucial, but they do not seem sufficient to contain sexual risk behaviours among MSM in France, despite the wide availability of screening, condoms and information and the fact that MSM represent a highly educated sub-population”.
In the United Kingdom, the Health Protection Agency (HPA) is also rolling out the use of recent infection tests. Whereas a 2007 study from Brighton estimated that half of new diagnoses in gay men were recent infections, the HPA’s preliminary results for 2009 suggest much lower figures - one-in-five for gay men, and one-in-ten for heterosexuals.