A Controlled Trial of Nonoxynol 9 Film to Reduce Male-to-Female Transmission of Sexually Transmitted Diseases

Abstract

BACKGROUND Nonoxynol 9 is a proved spermicide, but whether it is also a microbicide is uncertain. A truly effective vaginal microbicide would reduce the susceptibility of women to sexually transmitted diseases, including infection with the human immunodeficiency virus (HIV). METHODS We enrolled 1292 HIV-negative female sex workers in Cameroon and enrolled them in a double-blind, placebo-controlled study in which the participants were randomly assigned to use either a film containing 70 mg of nonoxynol 9 or a placebo film, inserted into the vagina before intercourse. All of the women were provided with latex condoms and were instructed to have their male sexual partners use them. At monthly follow-up visits, we examined the women with a colposcope for genital lesions, tested endocervical specimens for gonorrhea and chlamydia infection with DNA probes, tested for HIV infection, and treated the women for curable sexually transmitted diseases. RESULTS The rates of HIV infection (cases per 100 woman-years) were 6.7 in the nonoxynol 9 group and 6.6 in the placebo group (rate ratio, 1.0; 95 percent confidence interval, 0.7 to 1.5). The rates of genital lesions were 42.2 cases per 100 woman-years in the nonoxynol 9 group and 33.5 in the placebo group (rate ratio, 1.3; 95 percent confidence interval, 1.0 to 1.6). The rates of gonorrhea were 33.3 and 31.1 cases per 100 woman-years in the nonoxynol 9 and placebo groups, respectively (rate ratio, 1.1; 95 percent confidence interval, 0.8 to 1.4). The corresponding rates of chlamydia infection in the nonoxynol 9 group and the placebo group were 20.6 and 22.2 per 100 woman-years (rate ratio, 0.9; 95 percent confidence interval, 0.7 to 1.3). The women reported that condoms were used during 90 percent of sexual acts. CONCLUSIONS The use of a nonoxynol 9 vaginal film did not reduce the rate of new HIV, gonorrhea, or chlamydia infection in this group of sex workers who used condoms and received treatment for sexually transmitted diseases. The potential of nonoxynol-9 to reduce women's susceptibility to sexually transmitted diseases (STDs) was investigated in a double-blind, placebo-controlled trial conducted among 1170 HIV-negative sex workers in Cameroon. Participants were randomly assigned to receive either a film containing 70 mg of nonoxynol-9 (n = 595) or a placebo film (n = 575). Women in both groups were provided with latex condoms for their male partners. At monthly follow-up visits during the 12-month study period, colposcopy was used to examine women for genital lesions, endocervical smears were tested for gonorrhea and chlamydia, HIV testing was performed, and curable STDs were treated. Nonoxynol-9 film failed to confer any additional protection against infection with HIV, gonorrhea, or chlamydia beyond that provided by condoms alone and STD treatment. The rates of genital lesions were 42.2 cases per 100 woman-years in the nonoxynol-9 group and 33.5 in the placebo group (rate ratio (RR), 1.3; 95% confidence interval (CI), 1.0-1.6). The majority of genital lesions in the nonoxynol-9 group were external. The rates of gonorrhea were 33.3 and 31.1 cases per 100 woman-years in the nonoxynol-9 and placebo groups, respectively (RR, 1.1; 95% CI, 0.8-1.4), while those of chlamydia were 20.6 and 22.2 cases per 100 woman-years, respectively (RR, 0.9; 95% CI, 0.7-1.3). Finally, there were 6.7 cases of HIV infection per 100 woman-years in the nonoxynol-9 group and 6.6 in the placebo group (RR, 1.0; 95% CI, 0.7-1.5). Condoms were used during 90% of sexual acts.