Barrier contraceptive use and HIV infection among high-risk women in Cameroon

To measure the association between spermicide use and HIV infection, adjusting for condom use, and to measure the association between condom use and HIV infection, adjusting for spermicide use.

Prospective study of women using nonoxynol-9 (N-9) spermicides and latex condoms, with up to 12 monthly clinic visits for interviews, examinations and tests, and re-supply.

A total of 273 HIV-negative women with multiple sexual partners were enrolled, given latex condoms and N-9 vaginal spermicidal suppositories, and advised to use both every time they had sexual intercourse. Participants recorded data on sexual activity on pictorial coital logs. New HIV infections were detected and confirmed by quarterly enzyme-linked immunosorbent assays and Western blots, respectively.

Nineteen HIV infections occurred during mean follow-up of 8.1 months (an incidence rate of 10.4 infections per 100 women-years). The adjusted HIV rate ratio (RR) was 0.1 [95% confidence interval (CI), 0.1-0.6] for more consistent compared with less consistent spermicide users; and 1.1 (95% CI, 0.4-2.9) for more consistent compared with less consistent condom users. Among the subgroup of experienced condom users, the RR for more versus less consistent condom use was 0.3.

This is the first epidemiological evidence that N-9 spermicides can reduce the incidence of HIV infection. A more definitive randomized clinical trial is urgently needed.