title: Recruitment, screening and characteristics of injection drug users participating in the AIDSVAX B/E HIV vaccine trial, Bangkok, Thailand.
abstract: OBJECTIVE
  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 < or = 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.
authors.affiliation: Thailand Ministry of Public Health-US Centers for Disease Control and Prevention Collaboration, Nonthaburi. jwt0@tvc.or.th
authors.forename: Suphak
authors.initials: S
authors.lastname: Vanichseni
authors.forename: Jordan W
authors.initials: JW
authors.lastname: Tappero
authors.forename: Punnee
authors.initials: P
authors.lastname: Pitisuttithum
authors.forename: Dwip
authors.initials: D
authors.lastname: Kitayaporn
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Mastro
authors.forename: Eiam
authors.initials: E
authors.lastname: Vimutisunthorn
authors.forename: Frits
authors.initials: F
authors.lastname: van Griensvan
authors.forename: William L
authors.initials: WL
authors.lastname: Heyward
authors.forename: Donald P
authors.initials: DP
authors.lastname: Francis
authors.forename: Kachit
authors.initials: K
authors.lastname: Choopanya
mesh_terms: D016915:AIDS Vaccines; D000328:Adult; D001294:Attitude to Health; D015331:Cohort Studies; D004311:Double-Blind Method; D005260:Female; D015658:HIV Infections / Q000150:complications / Q000517:prevention & control*; D018023:HIV Seronegativity; D015497:HIV-1; D006801:Humans; D008297:Male; D008875:Middle Aged; D010353:Patient Education as Topic; D018579:Patient Selection; D012309:Risk-Taking; D012747:Sexual Partners; D015819:Substance Abuse, Intravenous / Q000150:complications*; D011795:Surveys and Questionnaires; D013785:Thailand
chemical_list: D016915:AIDS Vaccines; C112734:AIDSVAX