The World Health Organization is warning that a commonly used contraceptive compound does not prevent HIV infection and may even increase the risk of getting it.
Most contraceptives on the market used to kill sperm contain the chemical nonoxynol-9, abbreviated as N-9. Laboratory studies in the 1970s and 1980s showed that N-9 could inactivate organisms that cause several sexually transmitted diseases. This raised hopes that it could be used as a microbicide, a substance toxic to such diseases, hopefully against HIV.
But studies involving sex workers in Africa and Asia in the late 1990s revealed that the product failed to live up to the hope. As a result, the World Health Organization convened a meeting of medical experts to review the research. Their recommendations, issued Friday, are clear not only about N-9's failure to protect against HIV, but also its inability to prevent two other common venereal diseases, cervical gonorrhea and chlamydia.
"We are certainly recommending this product not be used at all in terms of HIV prevention, or in terms of preventing some other sexually transmitted infections," said Dr. Tim Farley, a World Health Organization reproductive health expert, who participated in the review of the N-9 data. "This product has no advantages from that point of view," he added. "Among people who are not at risk for HIV infection or sexually transmitted infections, spermicides are an option for people who want to avoid unwanted pregnancy."
The new World Health Organization report cites two studies showing that, in many cases, spermicides containing N-9 actually increase susceptibility to HIV. Other research suggests a possible reason: N-9 irritates the vaginal and rectal walls. The resulting ulcers invite infection. The report says the frequency of this irritation increases as N-9 use goes up.
Therefore, Dr. Farley says, N-9 should be discarded as a condom lubricant. "There's no evidence that nonoxynol-9 actually improves the performance of condoms in terms of preventing pregnancy or in terms of preventing any sexually transmitted infection," he said. "So there is no advantage to adding nonoxynol-9 to condoms. And, in fact, nonoxynol-9 condoms have a shorter shelf life than condoms lubricated with silicone."
N-9's disappointing performance has led the United Nations AIDS program to call for more research into microbicides. Public health officials are seeking an odorless, tasteless compound that a woman could apply privately, since many women around the world do not have the power to refuse sex or require their partners to use condoms.