Recruitment, screening and characteristics of injection drug users participating in the AIDSVAX B/E HIV vaccine trial, Bangkok, Thailand.
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.
Vanichseni
Suphak
S
Thailand Ministry of Public Health-US Centers for Disease Control and Prevention Collaboration, Nonthaburi. jwt0@tvc.or.th
Tappero
Jordan W
JW
Pitisuttithum
Punnee
P
Kitayaporn
Dwip
D
Mastro
Timothy D
TD
Vimutisunthorn
Eiam
E
van Griensvan
Frits
F
Heyward
William L
WL
Francis
Donald P
DP
Choopanya
Kachit
K
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
D016915:AIDS Vaccines; C112734:AIDSVAX