The effectiveness of barrier methods of contraception in preventing the spread of HIV

Abstract

Because barrier methods provide protection against bacterial sexually transmitted diseases, these methods are valuable public health adjuncts irrespective of their effect on HIV. Male latex condoms offer substantial protection against HIV infection. Women at risk of sexual acquisition of HIV infection need one or more prophylactic methods that they can control. While the available spermicide products may serve this purpose, current data do not allow firm casual inferences. Large and well designed epidemiologic studies are required to examine the association between female use of barrier methods and HIV infection. These are difficult and costly to perform, however, and to date have yielded conflicting results. Finally, prospective studies in high-incidence cohorts are necessary, and the relationships between spermicide use, local irritation, the vaginal flora and HIV incidence rates must be clarified.

PIP: The effectiveness of barrier methods of contraception in preventing sexually transmitted diseases (STDs) such as human immunodeficiency virus (HIV) has been assessed in vitro studies and epidemiologic research. Both types of studies have indicated that consistent use of high-quality latex condoms confers substantial protection against HIV transmission. Less certain is the capability of nonoxynol-9 to inactivate HIV. Of concern are several studies indicating that 1-8% of female nonoxynol-9 users experience signs and symptoms of tissue irritation, which can facilitate HIV transmission. These findings may reflect overenrollment of women with a high incidence of STDs and above-average (more than one per day) spermicide doses. Meetings sponsored by the World Health Organization and the US Public Health Service during 1993-94 reached consensus on five ethical and methodological principles to govern studies investigating whether currently available nonoxynol-9 spermicides reduce the incidence of HIV infections: 1) a randomly allocated controlled trial in which all participants are given male condoms; 2) allocation of half the women to an active spermicidal product and the other half to a placebo product; 3) counseling participants to use both a condom and the vaginal product at every coital act; 4) sufficient study size to measure HIV rate ratios within frequency strata; and 5) inclusion of colposcopic examinations and regular appraisal of participant safety by a data and safety monitoring board. Studies of less irritating yet effective spermicidal compounds, the determinants of consistent use of barrier methods, and the impact of social marketing are also recommended.