Undiagnosed HIV infection among men who have sex with men (MSM) in Vancouver, Canada
R. Hogg1, D. Moore1, S. Kanters1, R. Gustafson2, T. Trussler3, R. Marchand3, P. Banks4, M. Kwag2, M. Comptom2, A. Schilder1, M. MacGuire5, S. Ogunnaike-Cooke5, M. Perrin5, T. Wong5, C. Archibald5, W. Michelow1, M. Gilbert6, The Man Count Study Team
1BC Centre for Excellence in HIV/AIDS, Vancouver, Canada, 2Vancouver Coastal Health, Vancouver, Canada, 3Community Based Research Centre, Vancouver, Canada, 4Health Initiative for Men, Vancouver, Canada, 5Public Health Agency of Canada, Ottawa, Canada, 6BC Centre for Disease Control, Vancouver, Canada
Background: MSM account for the majority of HIV infections in Canada. The burden of undiagnosed HIV-infection in MSM in Vancouver is unknown. We examined the prevalence and context of undiagnosed HIV infection among a sample of this population.
Methods: The Man Count Study recruited participants from August 1, 2008 to February 28 2009 through community venues which cater to MSM. Men aged ≥ 18 years completed a self-administered questionnaire and provide a dried blood spot (DBS) for HIV testing. Stored plasma samples were re-tested using the STARHS algorithm to determine recent infection.
Results: 1139 participants provided samples for DBS and 959 self-reported their status as HIV-negative or unknown. Of these 28 (2.9%) tested HIV-positive which represented 13% of the 206 positive tests in the study. Of these 28 tests, 9 (32%) were classified as recent infections by detuned assay. 20 individuals (71%) had previously been tested for HIV and had undergone a median of 2 HIV tests (IQR 0 – 4 tests) in the previous 2 years. The most common reported reasons for the 16 individuals not known to have tested in the previous 2 years included: not wanting to know (n=4) or being unable to cope with the result (n=4); a conviction that they were already HIV-infected (n=4); not having the initiative to get tested (n=4) and concern about the impact on their relationships (n=5). 82% of these men reported using at least one behavioural measure to reduce their risk for HIV infection. Overall, 10 (50%) of 20 respondents felt that they were very unlikely or unlikely to acquire HIV during their lifetime.
Conclusion: Undiagnosed HIV infection accounts for a small, but important proportion of HIV-positive MSM who attend venues catering to gay or bisexual men. Strategies to reduce undiagnosed infections need to consider reducing barriers to testing and address perceptions of risk.