Objectives The use of a mobile van (MV) for screening for HIV and other sexually transmitted infections (STIs) is effective at reaching at-risk populations. The aim of this study was to compare behaviour characteristics and HIV and syphilis prevalence between subjects tested at a MV offering voluntary counselling and testing and those tested at three STI clinics in Guatemala.

Methods Over 28 months, female sex workers (FSWs), men who have sex with men/transgenders (MSM/TG), and people not reporting being a member of a risk group (NR) were offered HIV and syphilis rapid tests and interviewed about their sociodemographic and risk behaviour.

Results 2874 subjects were tested (MV, 1336 (46%); clinics, 1538 (54%)). The MV screened 73% of FSWs and 73% of the MSM/TG, and detected 19% of HIV and 69% of syphilis cases. HIV prevalence was significantly higher (p<0.001) at the STI clinics than at the MV for both NR and MSM/TG groups (NR, 7% vs 1%; MSM/TG, 8% vs 1%, respectively). A significantly higher proportion of MSM/TG screened at the STI clinic reported having had a prior HIV test (MV, 21%; clinics, 41%; p<0.001), whereas more FSWs tested in the MV reported having multiple partners and using condoms during their last sexual intercourse.

Conclusions The higher prevalence of HIV and syphilis at the STI clinics suggests that they successfully identified high-risk subjects. In particular, the NR group showed higher than expected HIV and syphilis prevalence. Innovative approaches such as the use of a MV helped to increase access to other hard-to-reach groups such as MSM/TG and FSWs.