This poster was presented at the 10th Annual Canadian Conference on HIV/AIDS Research in Toronto in June 2001. These data have also been presented at the CANVAC conference in Lake Louise, Alberta, in April 2001.

Unstable housing and belief of infection predict willingness to 
participate in a vaccine trial among young gay and bisexual men in Vancouver

Jacqueline M. O'Connell (3,4), Keith Chan (3), Magdalena A. Piaseczna (1), Nancy McLean(1), Steve Martindale (2), Robert Remis (4,5), Robert S. Hogg (3,4)

1) The Vancouver Vaccine Trial;
2) the Vanguard Project;
3) BC Centre for Excellence in HIV/AIDS;
4) CANVAC; and
5) the University of Toronto.

Jacqueline O'Connell presenting her poster at the 2001 CAHR Conference in Toronto.

OBJECTIVES:

To better understand behavioural and epidemiological aspects of HIV vaccine trials - especially factors associated with willingness to participate - we assessed the extent to which HIV-negative Vanguard Project participants would be willing to participate in future HIV vaccine trials. We also identified predictors of willingness to participate (WTP) in an HIV vaccine trial.

METHODS:

Since May 1995, young gay and bisexual seronegative men aged 15 to 30 have been recruited into an ongoing prospective study of HIV incidence and risk behaviors in the Greater Vancouver region.

Socio-demographics, sexual risk taking, social and emotional stability (MOS-SF and Rosenberg scores) and beliefs about HIV-issues were collected from self-administered questionnaires.

Participants were asked "If another HIV vaccine were tested in Canada on people who don't have HIV, would you be interested in participating in a study to see if it works?" Participants responding "Yes" or "probably" were considered to be WTP.

Contingency table analysis compared willing versus unwilling subjects, according to socio-demographic and risk-taking variables. Logistic regression models identified independent predictors of WTP in an HIV-vaccine trial. All possible two-way interactions were examined.

RESULTS:

Of 505 respondents, fewer participants were WTP (42%) than not (58%). WTP participants were more likely to be younger, unemployed, live in unstable housing, and to have injected drugs in the past year or in their lifetimes (Table 1).

WTP participants reported more sex partners in the past year or lifetime and were more likely to have casual sex partners. Although WTP participants were more likely to have unprotected receptive anal sex with casual partners, they were less likely to have insertive anal sex with casual partners (Table 2).

WTP participants had more HIV tests per year and were more likely to believe they had been infected with HIV in the past year (Table 3). WTP participants were also more likely to be depressed and marginally more likely to have lower self-esteem (Table 3). There was no association between WTP and ethnicity, involvement in the sex trade, education, income, sex with HIV+ partners, or sex with regular partners.

In multivariate analysis (Table 4), unstable housing and belief of likely being infected in the past year were the only independent predictors of WTP.

CONCLUSIONS:

Vanguard participants living in unstable housing and with a high-perceived threat of HIV infection were more likely to express willingness to participate in an HIV-vaccine trial.

Men with higher depression scores and lower social support were also significantly more WTP, suggesting that emotional need may be a major motivating factor affecting WTP for some young MSM.

Since higher-risk and emotionally or socially unstable individuals in our cohort are more likely to be WTP, HIV vaccine trial design must include measures that safeguard the psychological and physical health of potential participants.