Is there an HIV vaccine for heterosexuals at risk for HIV-1 transmission and how effective is it?

Updated: Mar 05, 2020
  • Author: Delia M Rivera, MD; Chief Editor: Russell W Steele, MD  more...
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A study from Thailand suggests a possible benefit of vaccines in heterosexuals at risk for HIV-1 transmission. [57] In the randomized, multicenter, double-blind, placebo-controlled trial by Rerks-Ngarm et al, 16,402 healthy participants aged 18-30 years received either 4 priming injections of recombinant canarypox vector vaccine (ALVAC-HIV [vCP1521]) plus 2 booster shots of recombinant glycoprotein 120 subunit vaccine (AIDSVAX B/E) or placebo.

In the per-protocol analysis, which excluded subjects who seroconverted during the vaccination series, the vaccine efficacy was 26.2%. In the modified-intention-to-treat analysis, which excluded subjects who had baseline HIV-1 infection, the vaccine efficacy was 31.2%. However, the 95% confidence intervals in these analyses were extremely wide (-13.3 to 51.9 and 1.1 to 52.1, respectively), which precludes concluding that the vaccine had proven efficacy. [57]

Among study subjects who developed HIV-1 infection, viremia and CD4+ T cell counts were unchanged by vaccination. This suggests that, if infection did occur, there was no apparent immunologic benefit from having received the vaccine.

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