MONDAY, Oct. 7 (HealthDay News) -- For individuals at high risk of HIV-1 infection, a DNA prime-recombinant adenovirus type 5 boost (DNA/rAd5) vaccine regimen lacks efficacy, according to a study published online Oct. 7 in the New England Journal of Medicine to coincide with presentation at the AIDS Vaccine 2013 meeting, held from Oct. 7 to 10 in Barcelona, Spain.
Scott M. Hammer, M.D., from Columbia University in New York City, and colleagues randomized 2,504 men or transgender women who have sex with men to receive DNA/rAd5 vaccine (1,253 participants) or placebo (1,251 participants). The authors sought to examine the efficacy of the vaccine regimen among those at increased risk of HIV-1 infection.
Vaccinations were halted in April 2013 for lack of efficacy. In the primary analysis, the researchers found that week 28+ infection (HIV-1 acquisition from week 28 through month 24) was diagnosed in 27 and 21 participants in the vaccine and placebo groups, respectively (P = 0.44). The mean viral-load set points were 4.46 and 4.47 HIV-1 RNA log10 copes per milliliter in the vaccine and placebo groups, respectively. A lack of vaccine efficacy was also noted in analyses of all infections (41 in the vaccine group and 31 in the placebo group; P = 0.28). The vaccine regimen side effect profile was acceptable.
"Our study gave a definitive, albeit disappointing, result but should provide useful information as newer vaccine regimens and approaches are developed," the authors write.
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