A microbicidal vaginal gel called Carraguard doesn't protect women from HIV infection. That's the conclusion of a study that included more than 6 200 sexually-active, HIV-negative women at three sites in South Africa.
The women were given either Carraguard or a placebo gel and told to use one applicator of gel and a condom each time they had vaginal sex. The women, who were followed for up to two years, visited a clinic every three months to have tests for HIV infection and pregnancy, pelvic examinations, risk reduction counselling, and treatment for curable sexually transmitted infections and vaginal infections.
The rate of HIV-infection among women using Carraguard was 3.3 per 100-woman years, compared with 3.8 per 100-woman years in the placebo group. Rates of self-reported gel use were similar in both groups (96.2% Carraguard, 95.9% placebo), but applicator testing indicated that actual gel use was much lower (41.1% Carraguard, 43.1% placebo). Self-reported condom use was 64.1% for both groups.
The findings were published in The Lancet.
No single method safe
"This study did not show Carraguard's efficacy in prevention of male-to-female transmission of HIV, although no safety concerns were recorded.
"Low levels of gel use could have compromised the potential to detect a significant protective effect. Although the results from this and other completed microbicide efficacy trials have been disappointing, the search for female-controlled HIV prevention methods must continue," wrote researchers from the Population Council in New York City and their colleagues.
Carraguard, a carrageenan-based compound, was developed by the Population Council. In an accompanying comment, Dr Willard Cates and Dr Paul Feldblum of Family Health International in North Carolina, wrote that no single method of HIV prevention will be adequate.
"Rather a combination of partly effective prevention approaches will be bundled into packages targeted to specific populations.
"This bundling will involve behavioural, biomedical, and structural interventions, each designed to reinforce the effect of the other. The cumulative influence of combination prevention is our hope for thwarting the spread of HIV," they said. – (HealthDay News, December 2008)
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