The study, authored by the B.C. Centre for Excellence in HIV/AIDS in Vancouver and co-investigators in Toronto and Montreal , found that 21% of participants engaged in the riskiest form of sexual encounter during the 6 months before enrollment. That level of risk-taking did not increase during 18 months of follow-up, even among men who at study entry thought the vaccine being tested might provide some protection. The vaccine being tested was ultimately shown to be ineffective.
"These results are important and reassuring. They demonstrate that gay men can participate safely in HIV vaccine trials without a false sense of security that could lead to greater sexual risk-taking and new infections," said lead author, Dr. Tom Lampinen.
The findings emerged during the world's first clinical test of a preventative vaccine, AIDSVAX. The study data are now being used to answer additional questions concerning the sexual health of gay men.
Additional study results were presented by Lampinen last summer at the International AIDS Conference in Bangkok , Thailand underscore the importance of the behaviour that did not increase during the trial. Those results showed the biggest risk for new infection was in the minority of gay men who had unsafe sex with partners whose HIV status they didn't know. Their risk for acquiring HIV was eight times that of men who did not report such sex, and four times that among men who reported taking risks with HIV-positive partners.
p. 479 Sexual risk behaviour of Canadian participants in the first efficacy trial of a preventive HIV-1 vaccine -- T.M. Lampinen et al
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