The British Co-operative Clinical Group (BCCG)

limited worldwide availability of these therapies, added expense, lessened patient acceptability, and uncertainty of patient compliance with these therapies and regimens mitigate against their widespread use. In addition, a programme introducing widespread therapy for BV in populations with high BV prevalence, as found in Africa, would need to monitor antimicrobial resistance not only of the organisms characteristic of BV (to ensure continuing eYcacy) but ideally also of other micro-organisms. The one study which evaluated an intervention for BV (a single 2 g dose of metronidazole at two 10 month intervals) did not show a significant decline in BV prevalence in the intervention compared with the control group at either the first or second post-treatment measurements, compared with one another or with pretherapy prevalences. Although a modest decline occurred in the intervention group at the second post-treatment visit (46.6% v 53.8% in the control group), these prevalences were not statistically diVerent and quite close to the pretreatment values of 50.4% and 51.2%, respectively. There was no diVerence in HIV acquisition between the treatment and control groups. A substudy of pregnant women did show a diVerence in BV prevalence post partum (39.1% v 52.8%), and it may be because these women were studied an average of only 4 months following therapy. Again, no diVerence in HIV acquisition between the two groups was demonstrated. Given the therapeutic inadequacies for BV, and that the single study which evaluated a therapeutic intervention for BV to prevent HIV infection showed no significant eVect, approaches to prevention of BV would be attractive; however, prevention options are also limited. Why women acquire or reacquire BV is not well known and the recognised risk factors for BV—for example, multiple or new sex partners, are generally not easy to modify. Replacement of the altered flora of BV with hydrogen peroxide producing lactobacilli appears promising but requires further investigation. Intravaginal microbicides containing nonoxynol-9, which might be prophylactically used against STIs and HIV, are also active against some of the organisms that characterise BV, although data on the clinical use of nonoxynol-9 for prevention of BV are conflicting. Importantly, lactobacilli concentrations may decrease transiently after use of nonoxynol-9 and the eVects of chronic use of such agents need to be further evaluated. Data on the association between BV and HIV have shed light on an important risk factor for HIV infection. The challenge now is to determine how to reduce BV related HIV transmission. More research is needed on BV, its aetiology, and how to better treat and prevent it.