Table 2. Bivariate and Multivariate Predictors of willingness to participate in future vaccine trials among retaining group.

Demographics	RR (95% CI)	ARR (95% CI)
Study visit
Baseline 6 mo 12 mo	1.0 1.0 (0.9–1.1) 1.2 (1.1–1.4)**	1.0 1.1 (1.0–1.2) 1.2 (1.1–1.4)**
Gender
Female Transgender	1.0 0.9 (0.8–1.1)
Age
18–31 > 31–45 > 45	1.0 1.0 (0.8–1.1) 1.1 (0.8–1.3)
Origin
Spain Other European Country Latin America Africa Asia	1.0 1.0 (0.8–1.3) 1.2 (0.9–1.4) 1.0 (0.8–1.3) 1.1 (0.6–1.9)
Education
No studies Primary Secondary University	1.0 1.2 (0.98–1.4) 1.2 (1.01–1.4)* 1.1 (0.8–1.5)	1.0 1.2 (1.01–1.5)* 1.2 (1.02–1.5)* 1.2 (0.9–1.7)
Sexual Behavior (ever)
Heterosexual Homosexual Bisexual	1.0 0.8 (0.7–0.98)* 1.0 (0.7–1.3)	1.0 0.8 (0.7–1.00) 1.0 (0.8–1.3)
Risk Behaviors
Injection drug use (ever)	–
Non-injection drug use (ever)	1.0 (0.9–1.1)
Performs sex work in last 6months	–
Performs sex work in last month	–
Sex with a known HIV positive partner in last 6 mo
No Yes Unknown	1.0 1.0 (0.5–2.0) 0.8 (0.7–0.9)**
Sex with a known HIV positive partner in last month
No Yes Unknown	1.0 1.5 (1.3–1.7)** 0.8 (0.7–0.9)**	1.0 1.4 (1.2–1.6)** 0.7 (0.6–0.8)**
Sex with an IDU partner in last 6 mo
No Yes Unknown	1.0 1.1 (0.8–1.4) 1.2 (1.0–1.3)
Sex with an IDU partner in last month
No Yes Unknown	1.0 1.1 (0.8–1.4) 1.2 (1.0–1.3)*	1.0 1.4 (0.9–2.3) 1.3 (1.1–1.4)**
Sex with a partner using other drugs last 6 mo
No Yes Unknown	1.0 0.8 (0.7–1.0)* 0.9 (0.7–1.0)
Sex with a partner using other drugs in last month
No Yes Unknown	1.0 1.0 (0.9–1.2) 1.0 (0.9–1.2)
Sex with a partner having multiple sexual partners in last 6 mo
No Yes Unknown	1.0 1.0 (0.7–1.5) 1.0 (0.7–1.5)
Sex with a partner having multiple sexual partners in last month
No Yes Unknown	1.0 1.1 (1.0–1.2) 1.1 (0.9–1.3)
UA/V sex with steady or casual partner in last 6 mo	1.0 (0.9 - 1.1)
UA/V sex with clients in last 6 mo	1.0 (0.8–1.4)
Self reported STI symptoms in last 6 mo	1.1 (0.8–1.6)

*p < 0.05; **p < 0.01