New Study Questions Effectiveness of Nonoxynol-9 in HIV Prevention
August 18, 2000
At the International AIDS Conference, held in Durban, South Africa, from July 9-14, 2000, UNAIDS researchers presented results of a study of nonoxynol-9 (N-9). This study was designed to determine if N-9, a product widely used in spermicides, would be effective in preventing HIV transmission.
The UNAIDS study was conducted in several locations in Africa between 1996 and May 2000. Nearly 1,000 HIV-negative female commercial sex workers were enrolled in a trial of a gel containing N-9.
Participants were counseled in consistent and correct condom use and were asked to use a vaginal gel each time they engaged in sexual intercourse. Half of the women in the study were given the N-9 gel and half were given a placebo, neither the participants nor the researchers knew which product each woman had received.
Researchers found that the women who used the N-9 gel had become infected with HIV at about a 50% higher rate than the women who used the placebo. Further, the more frequently women used only N-9 gel (without a condom) to protect themselves, the higher their risk of becoming infected. Researchers concluded that N-9 did not protect against HIV infection and may have caused an increased rate of transmission. One possible reason is that women who used N-9 had more vaginal lesions which might have facilitated HIV transmission.
The Centers for Disease Control and Prevention (CDC) cautions that this study was conducted among women at very high risk who used a great deal of the product on a frequent basis. Therefore, the adverse effects might not be seen at the same level by women using spermicides with N-9 less frequently or in different formulations.
Nonetheless, the CDC reports that, given that N-9 has now been proven ineffective against HIV, the possible risk with no benefit indicates that N-9 should not be recommended as an effective means of HIV prevention.
As a result of this data, UNAIDS and CDC will soon hold consultations to consider officially revising public health guidelines for the United States regarding N-9 for HIV- and pregnancy-prevention in populations at high risk for HIV. In the interim, the CDC suggests that "any community delivering hierarchical prevention messages that counsel individuals who can't use a condom to consider spermicides with N-9 for HIV-prevention should immediately change these messages." Further, it suggests that individuals using N-9 as a microbicide, a chemical barrier to HIV and STD transmission, to protect themselves from HIV transmission during anal intercourse should be informed of the ineffectiveness of this agent and warned of the potential risk of this practice.
CDC will also reevaluate recommendations regarding condoms lubricated with N-9. In the interim, while N-9 will not offer any additional protection against HIV, a condom lubricated with N-9 is better than no condom at all. However, condoms without N-9 may ultimately prove a better option for HIV prevention.
The CDC concludes that these findings point to the need for accelerated efforts to identify safe and effective microbicides, especially for those individuals who are unable to access condoms or negotiate their use.
For more information:
Letter to Colleagues from Helene D. Gayle, M.D., M.P.H., Director, National Center for HIV, STD, and TB Prevention, Centers for Disease Control and Prevention, August 4, 2000.
This article was provided by Sexuality Information and Education Council of the United States. It is a part of the publication SHOP Talk: School Health Opportunities and Progress Bulletin.