A vaginal gel used to reduce a woman’s risk of contracting AIDS has shown to be even more effective in reducing exposure to genital herpes. Researchers at the National Institutes of Health, Gilead Sciences, Inc., and universities in Belgium and Italy give hope for new prevention options as the microbicide gel could lower the incidence of herpes in women around the world, according to the New York Times.

Gilead, maker of the drug tenofovir, the anti-AIDS drug that is the gel’s active ingredient, is undecided about moving forward with obtaining approval for the American market. Other than the millions of dollars it would need to invest in seeking approval, “it would be three to four years before we were ready to submit data” to the Food and Drug Administration, Norbert W. Bischofberger, Gilead’s chief scientific officer.

Genital herpes is more common than AIDS. Estimates are as high as 20 percent of all sexually active adults having herpes according to the World Health Organization. The Centers for Disease Control and Prevention estimates that 21 percent of sexually active women in the United States have it, including 16 percent of all white women and 48 percent of all black women.

While not fatal, infection can be painful with blisters that resemble cold sores. Transmission can occur even when a condom is used (about 50% of the time) and when neither partner has sores. Unlike AIDS, genital herpes can be transmitted by skin-to-skin contact, not only via semen or vaginal fluid.

Tenofovir works by disrupting an enzyme that the herpes virus needs to duplicate itself. Using tonsil and cervical cultures in a laboratory setting, the drug lowered herpes viral levels by as much as 99 percent. Testing for the final gel trial was done in South Africa because of the high AIDS rates in that country. But, earlier tests for safety and acceptability were done in several countries, including the United States. Neither American nor South African couples found the gel unpleasant, though gay men found it too watery, so new formulations for that demographic are in pre-production phase.