What is a Vaginal Microbiome Transplant?

Starting in 2015, five patients had fluid inserted into their vaginas in an experimental treatment for their intractable, recurrent bacterial vaginosis (BV). The fluid they each received? Material collected from someone else’s vagina. And yep...it’s pretty much exactly like you’re picturing it. The study participants had struggled with vaginal health issues for years, which had been wreaking havoc on their personal lives. They were fed up, and this was a drastic test of a solution to their problem. So...did it work?

What is a vaginal microbiome transplant?

Your vaginal microbiome is the diverse community of microorganisms living in your vagina. They do all kinds of important work to keep you healthy, but this community can also get out of balance. Previously, many studies have tried to treat chronic vaginal imbalances like BV or yeast infections with probiotics, or supplementation of beneficial bacteria. This is typically a capsule, taken orally, or a vaginal suppository (usually, these will contain Lactobacillus species). The probiotic approach has shown mixed results in studies so far, with nothing particularly definitive about its efficacy, so several teams have instead come at the problem from a group mindset—you can’t just relocate the star of the show, it has to come with the whole supporting cast too. In other words, a new wave of experiments transfer the whole vaginal microbiome, in the form of unaltered vaginal fluid, from a healthy donor with no recent history of BV... directly into the receiving patient’s vagina.  

This concept was partially inspired by the recent success of fecal microbiota transplantation (FMT). FMT have provided effective (but still experimental) solutions for recurrent infections of the digestive tract by a destructive bacterium called Clostridioides difficile (or C. diff). FMTs have also been experimentally used to treat ulcerative colitis. 

In this recent clinical trial of vaginal microbiome transplants (VMBTs), all of the patients had at least a short-term reprieve from their BV, and many experienced long-term remission. Some participants needed further transplantation to keep them in a BV-free state, but none experienced any negative side effects of receiving someone else’s vaginal bacteria. This study was a very small pilot program—just five patients. It’s really just a proof of concept at this point, so there’s still the possibility that risks, complications, and unknown long-term side effects could pose problems for some. But tens of similar clinical trials are now underway worldwide (you may even be able to sign up for one!), and they’re an exciting first look at a creative potential solution to a problem that plagues millions of people with vaginas. 

It’s not an exact science

This experimental treatment also showed that a vaginal microbiome transplant is not a one-size-fits-all approach. Some of the patients needed multiple top-up transplants, or needed to have their donor switched out before the treatment started having longer term results. This indicates that all kinds of variables—like the species in the donor sample, or the recipient’s baseline vaginal environment—need to be properly matched to one another for the treatment to be truly effective. Here’s where precision science comes in. With any kind of microbial transplant, extensive testing is done on both the donor and the recipient to track the changes that occur over the course of the treatment. This also ensures that no pathogens (or, in the case of VMBTs, even accidental sperm lingering in the donor’s body) are transferred to the recipient. Genetically sequencing the donor’s and recipient’s microbes throughout the process tells us what kinds of organisms can establish themselves and thrive in each recipient, and how those communities vary based on the recipient’s vaginal characteristics and even the composition of their original dysbiotic (aka out-of-balance) state. 

This kind of testing to understand what bacteria and fungi is present in a sample is exactly the same as the kind we do here at Juno Bio. 

The future of microbial transplantation for women’s health

While it’s still early days for VMBTs, we can look to the gut microbiome space to see where this might lead in reproductive health. Thanks to FMTs, ‘stool banks’ like OpenBiome have been created. Much like a bone marrow registry, this gives donors the opportunity to have their microbiomes sequenced so that doctors can match their patient with a donor whose microbial community is best suited to their needs. As we discover more about the interplay of organisms, patient immune systems, and other factors, a precision approach like this may be offered to patients who need all kinds of microbial transplants — including vaginal. 

We know how important the vaginal microbiome is to overall health. It can influence your risk of giving birth to a child pre-term, can affect your sexual health, and can alter your sense of self. The future is bright with solutions, we just need to keep pushing to make sure they receive the support they need to become a reality.