Condom and nonoxynol-9 use and the incidence of HIV infection in serodiscordant couples in Zambia
Hira, S.K.; Feldblum, P.J.; Kamanga, J.; Mukelabai, G.; Weir, S.S.; Thomas, J.C.
International Journal of Std and Aids 8(4): 243-250
1997
ISSN/ISBN: 0956-4624 PMID: 9147157 DOI: 10.1258/0956462971919994Document Number: 267995
The aim of this study was to measure the effectiveness of latex condoms and of nonoxynol-9 [N-9] spermicides, in preventing HIV transmission in 110 heterosexual HIV-serodiscordant couples in Lusaka. Each couple was examined at clinic visits scheduled at 3-month intervals for one year or more per couple, or until seroconversion or discontinuation. Couples were given condoms and their choice of 3 N-9 products and advised to use both at every intercourse. Mean follow-up was 17.6 months. 78% of coital episodes were protected by condoms, 85% by spermicides and 6.4% were unprotected. Fourteen seroconversions occurred (8.7 infections per 100 couple-years [c-y]). The rate was higher among seronegative men than seronegative women. Among couples who reported using condoms at every intercourse the infection rate was 2.3/100 c-y, compared with 10.7/100 c-y among couples using condoms less consistently (rate ratio [RR] 0.2; 95% confidence interval [CI] 0-1.6). Among couples who reported using N-9 at every intercourse, the seroconversion rate was 6.9/100 c-y; among couples who reported less than full-time N-9 use, the rate was 8.9/100 c-y (RR 0.8; 95% CI 0.2-2.8). Among the subset of female seronegatives, the N-9 RR was 0.5 (95% CI 0.1-3.8). However, when HIV rates were calculated according to N-9 consistency in coital acts when condoms were not used, there was no evidence of protection with higher N-9 use. Consistent use of latex condoms reduces the incidence of HIV infection, but the association between N-9 spermicides and HIV is less clear. The current study could not provide compelling data on the impact of N-9 spermicide use on risk of HIV infection, but was limited by its small size, as well as the consistency of concurrent condom use.