The widely used spermicide nonoxynol-9, long recommended as a way to stop the spread of AIDS, may actually increase the risk of catching the virus, at least among women who use it frequently, according to the surprising findings of a large study.
As a result, health officials said condoms used solely to prevent disease should not be coated with nonoxynol-9, although a condom with the spermicide is certainly safer than no condom at all. And they said the spermicide should also not be used for birth control by anyone at high risk of catching HIV.
Nonoxynol-9 is widely used around the world for contraception, and about one-third of lubricated condoms sold in the United States are covered with it. Nonoxynol-9 is a detergent formulated to kill sperm, but in the test tube it also wipes out HIV, and many have long assumed it helps protect people from the virus.
However, a study on prostitutes released today at the 13th International AIDS Conference showed just the opposite: Women using a nonoxynol-9 gel increased their risk of contracting HIV rather than lowering it.
“It is an understatement to say that we were extremely disappointed,” said Dr. Lut Van Damme of the Institute of Tropical Medicine in Antwerp, the study’s director.
The researchers now assume that nonoxynol-9, or N-9, increases the risk by irritating the vaginal lining, causing tears that give the virus a way to enter the body.
The prostitutes in the study applied N-9 up to 20 times a day, and there is no evidence that women who use it once or twice a day increase their risk of HIV. Nevertheless, Van Damme recommended that N-9’s long-term safety as a contraceptive be re-evaluated.
Study Used Almost 1,000 Prostitutes
The study began in 1996 on 990 prostitutes in South Africa, Benin, Thailand and Ivory Coast. They were randomly given either an N-9 gel called Advantage-S or a similar-looking but inactive vaginal moisturizer. The women were also urged to use condoms and given a free supply.
The study ended May 31, and the researchers were surprised by the results. Fifteen percent of the women using the N-9 gel had become infected with HIV, compared with 10 percent in the comparison group.
“This convincingly shows this product is not a good idea in a high-risk population,” said Dr. Joseph Perriens, who heads microbicide research at UNAIDS. “If you use nonoxynol-9, you are wasting your money, and you may be wasting your life.”
Dr. Ann Duerr, HIV chief in the reproductive health division at the U.S. Centers for Disease Control and Prevention, said the effects of the low amounts of N-9 on condoms are unclear. But given a choice, people who want to protect themselves from HIV should select those without the spermicide, even though condoms with the spermicide are safer than avoiding condoms entirely.
“For sexually transmitted disease prevention, our recommendation has been to use condoms with or without nonoxynol-9,” Duerr said. “Now it’s clear that N-9 does not add protection and may be harmful.”
Advantage-S spermicide is sold in the United States and China and manufactured by Columbia Laboratories of Miami. Howard Levine, its research director, said the company’s work shows the product is safe when applied up to four times a day. He attributed the study’s results to the prostitutes’ high use.
Despite the widely held assumption that N-9 stops HIV, earlier research raised doubts. The most recent, a study of 1,170 prostitutes in Cameroon, found a spermicide film did not prevent infection, although it offered no hint that it increased the risk, either. An earlier study found a higher infection rate in Kenyan prostitutes using an N-9 sponge, but the increase was not statistically meaningful.
Van Damme said two other large studies involving an N-9 gel called Conceptrol, being done on non-prostitutes in Africa, may have to be stopped. The CDC said today it had halted a study involving N-9 in Miami and Los Angeles.
Finding an HIV-killing lotion is a major goal of AIDS research, since it would offer an alternative to condoms. Several novel products are in early-stage human testing. Among these are PC-515 and Pro2000, both derived from seaweed.
The Bill & Melinda Gates Foundation, started by the Microsoft founder, said today it would donate $25 million to develop and test products to prevent the spread of AIDS and other sexually transmitted diseases.