ABSTRACT
Objective To investigate the dynamic change and associated risk factors of HIV sero-conversion rate in Beijing.Methods 809 sero-negative men who have sex with men (MSM) were recruited in the cohort from August to December in 2009.HIV sero-antibody,medicinal examination and behavior questionnaire interview were carried out every six months.Results 962 MSM with overall baseline prevalence of HIV infection as 6.34％ (61/962) together with 809 seronegative MSM,were enrolled in the cohort.Of the 809 sero-negative participants,95.1％ (769/809),85.5％ ( 692/809 ) and 71.0％ ( 574/809 ) of them were retained in the 6-month,12-month and 18- month follow-up visits,with 19,29 and 17 of them became HIV sero-conversion at 6-month,12-month,and 18-month follow-up visits and the HIV incidence rates appeared to be 5.47,12.37 and 6.86 per 100 person-years respectively.The HIV incidence was 7.59 per 100 person-years in the 18 months follow-up visit.Factors including:younger than 25-years old (HR =2.32,95％CI:1.39-3.87),having more than 8 MSM partners (HR=2.50,95％CI:1.49-4.20),less than RMB 2000 Yuan every month income (HR=1.76,95％CI:1.06-2.95 ),having more than 4 homosexual partners in the last six months (HR=3.50,95％ CI:2.11 -5.81 ),showing phimosis and redundant prepuce (HR=2.47,95％ CI:1.50-4.07 ) as well as positive syphilis test (HR=2.62,95％CI:1.53-4.49) etc.,were significantly associated with HIV incidence.Conclusion High HIV incidence was shown among MSM in Beijing and had spread fast in this population,calling for more favorable prevention measures to be taken.