A comparative analysis of HIV diagnoses in gay men in eight industrialised countries has found that while they decreased between 1996 and 2000, diagnoses went up by 3% a year from 2000 to 2005, researchers report in the June 2009 issue of the Annals of Epidemiology.
The researchers used national surveillance data compiled by public health bodies in the UK, the Netherlands, France, Germany, Spain (Catalonia only), Australia, the United States (25 states only) and Canada. These countries were chosen as a convenience sample of concentrated epidemics where the surveillance systems were broadly comparable (although not identical) and did not change too much during the period studied.
For the six countries with data from 1996 to 2000, the numbers of annual HIV diagnoses decreased by an estimated 5.2% per year.
However, for the eight countries with data from 2000 to 2005, annual diagnoses increased by 3.3% each year. The greatest annual rises were seen in four European countries (Germany 12%, France 11.3%, UK 9.6%, Netherlands 9.3%), whereas annual increases were below 5% in Spain, the United States, Canada and Australia.
Taking the six countries with data throughout the period studied, the number of diagnoses per 100,000 men in the population (i.e. including heterosexual men) dropped from 19.1 in 1996 to 14.6 in 2000, but increased to 16.6 in 2005.
The researchers also found that the median age at diagnosis increased from 34 to 36.
The team also collected data on reports of syphilis, and found that in five countries there were sharp increases in reports during 2000 to 2005. They believe this suggests that there were probably increases in risky sexual behaviour at this time, which would partially explain the increase in HIV diagnoses. However the researchers did not have other data that would indicate increases in risky sexual behaviour (e.g. self-reported prevalence of unprotected anal intercourse, collected with standardised questions in several countries).
The researchers also considered whether the increase in diagnoses could have been due to changes in HIV testing patterns among gay men. From the limited amount of data available, there was no indication of a consistent trend towards increased testing.
The authors note that with the internet, international travel and shared popular cultures, “trends in beliefs, risk practices, substance use and protective strategies that arise in one country may well emerge in others.” They call for more research into this resurgence in HIV diagnoses, and for greater investment in HIV prevention.
Sullivan PS et al. Reemergence of the HIV Epidemic Among Men Who Have Sex With Men in North America, Western Europe, and Australia, 1996–2005 Annals of Epidemiology 19: 423-431, 2009.