The protective effect of condoms and nonoxynol-9 against HIV infection.

Abstract

OBJECTIVES: Whether or not spermicides can reduce the risk of human immunodeficiency virus (HIV) transmission remains an important question for the control of heterosexual HIV transmission. The authors provide estimates from a reanalysis of one of the few observational studies on the efficacy of condoms and spermicides, used separately and together, per vaginal contact. METHODS: In this reanalysis, three different models were used to assess the efficacy of spermicides and condoms: linear (Pearl index), exponential (maximum likelihood), and monotonic (marginal likelihood). RESULTS: Reported use of barrier methods among 27,432 contacts was as follows: condoms plus nonoxynol-9, 39%; condoms alone, 25%; nonoxynol-9 alone, 24%; and unprotected, 11%. Under all three models, the results indicate a strong protective effect for spermicidal suppositories. The Pearl index indicated that spermicide alone is apparently efficacious, but the efficacy per contact cannot be quantified with this approach. Maximum likelihood estimates for the efficacy of nonoxynol-9 alone and condoms (with or without nonoxynol-9) were 100% (95% confidence interval [CI95] = 43%, 100%) and 92% (95% CI95 = 79%, 100%), respectively. CONCLUSIONS: The data from this observational study suggest that spermicides may be efficacious in reducing the risk of HIV transmission.

Ourselves, our bodies, our realities: an HIV prevention intervention for women with severe mental illness

“…Later studies provided conflicting evidence in the role of nonxynol-9 in HIV prevention, but suggested that it could be useful in STD prevention, and that it might be safe in lower doses. 32,33 Since the time of the development and pilot testing of this curriculum, the preliminary results of a Joint United Nations Programme on HIV/AIDS (UNAIDS) study of nonoxynol-9 and condom use at three African sites have shown that the microbicide is not protective in vivo against HIV transmission and may be facilitative in a high-risk population. 34 The model of including microbicides among the HIV prevention options for women, however, is valuable.…”

Combining several ordinal measures in clinical studies

“…In 1998, we developed a non-parametric method for analysing multivariate ordinal data to assess the overall risk of HIV infection based on di erent types of behaviour [4] or the overall protective e ect of barrier methods against HIV infection [36]. In short, one determines all rankings compatible with the partial ordering of the observed multivariate data and then computes a vector of scores as the average across these rankings.…”

Gynecologic issues in the HIV-infected woman

“…A study of female sex workers in Kenya demonstrated an increased HIV acquisition with spermicide and sponge use together, probably secondary to inflammation and ulcers caused by such frequent use of spermicides in this population (134), making the CDC hesitant to recommend spermicide use for HIV prevention. One reanalysis of an observational study suggests that spermicides indeed prevent transmission (135), but a metanalysis of multiple trials yields conflicting results, with a protective effect in one observational study and a nonsignificantly increased risk in one clinical trial (136). Seroinfected women with discordant partners should not use spermicides because of the potential for increased transmission to their partners (132).…”