The most recent Sexually Transmitted Infections Treatment Guidelines published in 2021 by the Centers for Disease Control and Prevention recommend against routine treatment of male sexual partners of women with bacterial vaginosis. But the guidance did include a pilot study describing a decrease in bacteria known to cause BV in treated male sexual partners, including Gardnerella vaginalis, Prevotella spp., Sneathia spp., Atopobium vaginae, Megasphaera spp. and Clostridia-like bacteria.
The authors of this pilot study have now completed an open-label, multicenter study in Australia published in the New England Journal of Medicine that randomized outpatient females diagnosed with BV (using a combined Amsel criteria and Nugent scoring) to a partner treatment group (where both female and male partner got treated) or to a control group (where only the female got treated).
BV treatment did deviate slightly from CDC STI Guidelines in the study, but only the metronidazole dosing was different as the intravaginal doses were in concordance with CDC guidance.
Male partners received metronidazole 400-mg tablets twice daily for seven days and were instructed to apply a 2-cm diameter of 2% clindamycin cream topically to the glans penis and upper shaft (under the foreskin if the male partner was uncircumcised) twice daily for seven days. Males and females were treated at the same time. Control group males did not get placebo cream. Both groups were instructed to avoid sexual contact for seven days. The primary endpoint was recurrence of BV within a 12-week follow up.
Follow up included questionnaires for symptoms, adherence and collection of vaginal samples. Females in both groups were asked to submit self-collected vaginal samples at home on day 8 after treatment and on week 8. Females in both groups were also asked to follow up in clinic at weeks 4 and 12 to obtain clinic vaginal samples to compare Nugent scores and Amsel criteria obtained at baseline. During this follow-up period, if females reported new symptoms or vaginal samples met criteria for BV again, then the female participants were sent back for extra clinic visits for treatment.
During the study period between April 2019 and November 2023, the authors randomized 137 patients, split 69 in the treatment and 68 in the placebo groups. The trial was stopped early because of the inferiority of the standard of care. Recurrence of BV within 12 weeks was 35% in the treatment group versus 63% in the control group, with the treatment group experiencing recurrence 63% less than the control group; hazard ratio, 0.37 (95% confidence interval, 0.22 to 0.61). Average time to recurrence was 73 days in the partner group versus 54 days in the control group (P < .001).
All women had an adherence to medications at least 70% of the time, while about 86% of the male partners had an adherence to medications at least 70% of the time, missing more clindamycin cream than metronidazole pills.
The current study shows that treating male partners with topical clindamycin and systemic metronidazole decreases BV recurrence in female partners. Because BV recurrence can be as high as 60% in previous studies, this study finally provides a treatment option to decrease the high morbidity of this infection. Limitations of the study include lack of diversity in the Australian study population and the elimination of 27 couples from primary analysis.
This study also reminds me that it is time to join Dr. Glaucomflecken on Infectious Diseases Rounds.