Vaginal-fluid transplants appeared to successfully treat devastating vaginal conditions that had failed all other treatments options, according to a small pilot study published this week in Nature Medicine.

The study comes amid a gush of enthusiasm for the transplants, often dubbed vaginal microbiota transplants (VMTs) . Though researchers are only now getting down to investigating their potential, many are optimistic that the microbe-toting fluid swaps will prove broadly successful at treating swaths of conditions in more rigorous trials.

In a recent conceptual study on screening potential fluid donors, Johns Hopkins researchers suggested that the transplants could “revolutionize the way we view and treat conditions affecting the female reproductive tract.”

With the mood set, a team of Israeli researchers had been working on a first exploratory trial since 2014. The trial included five women (aged 27 to 47), who all suffered from intractable cases of bacterial vaginosis (BV) but were otherwise healthy. BV is a condition marked by alterations to the microbial communities that typically reside in the vagina, which can lead to a range of problems—from malodorous vaginal discharge to increased risks of upper-genital-tract infections and pregnancy complications, as well as greater susceptibility to sexually transmitted infections.

The women had experienced at least four bouts of symptoms from their condition in the previous year and endured repeated antibiotic regimens to try to kick the condition without success. They all reported that their BV had significant effects on their lives, including harming their relationships and self-esteem.

Microbial migration

Those BV patients were treated with microbe-laden vaginal fluids collected from three rigorously screened donors. The three volunteers (aged 35 to 48) submitted extensive medical records, had no history of BV, tested negative for sexually transmitted infections and other conditions, and reported no use of various medications. All reported abstaining from sexual activity for at least a week prior to donating—two reported they had been sexually inactive for eight or more years, and one was in a 25-year monogamous relationship.

Analysis of their vaginal fluids suggested healthy vaginal microbial communities, which are typically dominated by Lactobacillus. In general, vaginal microbiomes are considered less complex and variable than those found in the intestines, despite also playing critical roles in health.

All of the transplant recipients were primed for the donor fluids with an intravaginal antibiotic regimen. The fluids were then transplanted within 60 minutes of collection.

Two of the recipients showed long-term BV remission after just one transplant. They reported improvement in symptoms within one week of the procedure and stayed in remission for their follow-up periods, which lasted up to 11.5 months. Two others ended up undergoing three transplants before achieving complete remission through their follow-up periods, which lasted up to 21 months. Genetic analyses suggested that the recipients’ vaginal microbiomes had shifted to look more like the donor communities.

The last recipient only achieved a partial resolution of BV, but her case was complicated by a throat infection that required her to take oral antibiotics after her first transplant. After that treatment, her BV symptoms returned. She underwent another transplant, which improved her symptoms and clinical signs of BV. But, at 6.5 months of follow-up, her vaginal microbial communities looked like a mix of her original community and the donor community.

“Collectively,” the authors conclude, “we report the feasibility of using VMT as a long-term treatment for recurrent, antibiotics-nonresponsive, and intractable BV.”

Now, with safety and benefits documented, “the efficacy of VMT as a treatment in intractable BV needs to be determined in randomized, placebo-controlled trials.” Currently, there are at least two such trials in the works.

Nature Medicine, 2019. DOI: 10.1038/s41591-019-0600-6 (About DOIs).