RESEARCH ARTICLE Participation of HIV preve m s

Full list of author information is available at the end of the articleBackground Men who have sex with men (MSM) are recognized as being at high risk for HIV infection in the Western world [1,2]. Recently, there have been reports of new or newly identified epidemics of HIV infection among MSM in Asia, Africa and Latin America [3,4]. Sexual transmission accounted for more than 70 % of new infections in China. Of these sexually transmitted new infections, MSM accounted for 32.5 % in 2009, which is almost a 3-fold increase from 12.2 % in 2007 [5,6]. Recent studies have documented dramatic increases in HIV prevalence and alarmingly high HIV incidence among MSM in major Chinese urban areas [7-9]. A national study targeting over 18,000 MSM in 61 cities reported an average HIV prevalence of 4.9%, with prevalence up to 20 % in several urban areas [10]. For example, in Chongqing, the largest municipal administrative unit in China with a population of 32 million, HIV prevalenc