Table 1.
Factors associated with willingness to participate in an HIV vaccine trial among injection drug users (n = 243).
| Variable | WTP (n=154) n (%) |
Not WTP (n=89) n (%) |
p-Valuea |
|---|---|---|---|
| Sociodemographics | |||
| Age mean (median) | 42.1 years (42.9) | 42.8 years (44.9) | 0.51 (t-test) |
| IQRb | 36.8–47.7 | 35.8–50.4 | |
| Gender | |||
| Female (reference) | 60 (39) | 26 (29) | 0.13 |
| Male | 94 (61) | 63 (71) | |
| Aboriginal ethnicityc | 54 (35) | 17 (19) | 0.01 |
| Education ≥high school | 90 (58) | 38 (43) | 0.02 |
| Employment | 46 (30) | 22 (25) | 0.39 |
| Unstable Housingd | 107 (69) | 59 (66) | 0.61 |
| Risk variables | |||
| Borrowed needlesd | 9 (6) | 6 (7) | 0.79f |
| Lent needlesd | 4 (3) | 6 (7) | 0.18f |
| Injection heroin ≥dailye | 43 (28) | 27 (30) | 0.69 |
| Injection cocaine ≥dailye | 13 (8) | 7 (8) | 0.88 |
| Smoking crack ≥dailye | 58 (38) | 36 (40) | 0.67 |
| Sex trade involvementd | 25 (16) | 8 (9) | 0.11 |
| Incarcerationd | 31 (20) | 12 (13) | 0.19 |
| Health service utilization | |||
| Attended needle-exchange program (ever vs. never) | 118 (77) | 63 (71) | 0.32 |
| Needle-exchange program ≥1/week | 68 (44) | 35 (39) | 0.46 |
| Injecting in Insite (ever vs.never) | 109 (71) | 70 (79) | 0.18 |
| Injecting in Insited | 89 (58) | 65 (73) | 0.81 |
| Drug/alcohol treatmentd | 75 (49) | 47 (53) | 0.54 |
| Psychosocial variables | |||
| Depression (≥16)g | 87 (66) | 53 (65) | 0.88 |
| Cognitive factors | |||
| Treatment optimism | |||
| By taking HIV medicines, an HIV+ person reduces the chance of infecting someone with HIV through sharing needlesh | 0.95 | ||
| By taking HIV medicines, an HIV+ person reduces the chance of infecting someone with HIV through unprotected sexh | 0.14 | ||
| Treatment optimism sum | 0.40 | ||
| Knowledge items correct vs. incorrect/do not know | |||
| 1 | 35 (23) | 27 (30) | 0.19 |
| 2 | 44 (29) | 21 (24) | 0.40 |
| 3 | 77 (50) | 36 (40) | 0.15 |
| 4 | 90 (58) | 52 (58) | 1.00 |
| 5 | 19 (12) | 13 (15) | 0.63 |
| 6 | 94 (61) | 49 (55) | 0.36 |
| 7 | 52 (34) | 39 (44) | 0.12 |
| 8 | 71 (46) | 40 (45) | 0.86 |
| 9 | 76 (49) | 33 (37) | 0.06 |
| 10 | 125 (81) | 71 (80) | 0.71 |
a
Two-tailed probability.
b
IQR, interquartile range.
c
First Nations, Métis, or Inuit.
d
Activities in past 6 months.
e
Current activities.
f
Fisher's exact test.
g
CES-D (20 item 4-point scale) standard cut-off score of ≥16.
h
5-Point Likert optimism scale ranging from “strongly disagree” to “strongly agree”