Objectives This study aimed to describe the epidemiology of HIV infection and sexually transmitted infections (STIs) among persons who attended voluntary counselling and testing (VCT) service for HIV and to assess whether the VCT programme reached the right population at risk in Taiwan.

Methods From 2006 to 2010, questionnaire interview, integrated pretesting and post-testing counselling, followed by serological tests for HIV, Treponema pallidum and Entamoeba histolytica were performed for all VCT clients; additional tests for Chlamydia trachomatis and Neisseria gonorrhoeae using PCR assays of urine specimens were provided when the assays became available in two periods.

Results During the study period, 10 198 VCT attendances occurred in 6863 clients, in whom 1685 (24.6%) had re-attendances. Male clients, men who have sex with men and clients with one-night stand and casual sexual partners were more likely to re-attend VCT service in the next 12 months. The overall STI prevalence was 3.5% for HIV infection, 2.2% syphilis, 1.0% amoebiasis, 4.7% chlamydia and 0.7% gonorrhoea. In logistic regression model, men who have sex with men were consistently independently associated with HIV infection, syphilis and amoebiasis. Among the repeaters, the incidence rate of HIV infection and syphilis was 3.4 and 1.6 per 100 person-years of follow-up, respectively. In Cox regression analysis, clients who used illicit non-injection recreational drugs and who practiced unprotected anal sex were at significantly higher risk of acquiring HIV infection and syphilis.

Conclusions With higher rates of re-attendances and STIs, the VCT programme reached the population most at risk for HIV and STIs compared with other screening programmes in Taiwan. The potential of VCT programme can be maximised in the prevention and control of HIV infection and STIs by providing tests for more STIs and counselling to avoid use of recreational drugs and to promote safe sex.