Suphak VanichseniJordan W. TapperoPunnee PitisuttithumDwip KitayapornTimothy D. MastroEiam VimutisunthornFrits Van GriensvenWilliam L. HeywardDonald P. FrancisKachit ChoopanyaBangkok Vaccine Evaluation GroupMahidol UniversityBangkok Metropolitan AdministrationThailand Ministry of Public HealthCenters for Disease Control and PreventionVaxGen, Inc.2018-07-242018-07-242004-01-23AIDS. Vol.18, No.2 (2004), 311-316026993702-s2.0-10744231887https://repository.li.mahidol.ac.th/handle/20.500.14594/21407Objectives: To describe recruitment, screening and baseline characteristics of injection drug users (IDU) participating in a phase III HIV vaccine (AIDSVAX®B/E; VaxGen, USA) trial and to compare enrollment characteristics between trial participants and 1209 IDU from a 1995-1998 vaccine trial preparatory cohort for changes that might impact trial design assumptions. Methods: Enrollment for both studies was conducted at Bangkok narcotic treatment clinics, where a standardized questionnaire was administered on demographics, risk behavior and incarceration history over the previous 6 months. Results: During 1999-2000, 4943 IDU were screened for enrollment; successful sources of recruitment included clinic attendees (43.4%), an IDU referral program (20.4%) and preparatory cohort participants (14.7%). Of those screened, 1689 (34%) were HIV seropositive (HIV subtype B 23.6%; subtype E 76.4%). Of the 2545 enrolled, 93.4% were male. Compared with cohort IDU, trial IDU were younger (mean age: 28.8 versus 31.3 years), better educated (secondary level or higher: 67.2% versus 58.7%), and less likely to inject drugs daily (39.4% versus 90.4%); they were more likely to have been incarcerated (78.4% versus 65.7%), have recently injected stimulants (14.8% versus 5.8%) and tranquilizers (11.5% versus 2.3%), and obtained needles/syringes from a source other than a pharmacist (7.2% versus 3.9%) (all P ≤ 0.003). Conclusions: IDU at high risk for HIV have been successfully enrolled in the AIDSVAX®B/E efficacy trial. Only minor epidemiologic differences were found at enrollment between trial and preparatory cohort IDU. The latter has proven critical in guiding trial design; results are expected in late 2003. © 2004 Lippincott Williams & Wilkins.Mahidol UniversityImmunology and MicrobiologyMedicineArticleSCOPUS10.1097/00002030-200401230-00022