Prevalence of HIV among men who have sex with men in Chongqing, China, 2006–2009: cross-sectional biological and behavioural surveys

Objective To assess the prevalence of HIV among men who have sex with men (MSM) in Chongqing, China from 2006 to 2009. Methods The authors used a snowball sampling method to perform a 3-month cross-sectional study each year from 2006 to 2009. Every participant was asked to complete a questionnaire about demographic and behavioural characteristics, and blood samples were taken for antibody testing for HIV and syphilis. Results A total of 953, 1015, 743 and 603 participants were investigated in 2006, 2007, 2008 and 2009, respectively. HIV prevalence rates were 10.9%, 12.8%, 10.6% and 19.1%, respectively. The rates increased by 2.3% averagely per year (p