Full transcript
Lucy Hope
Today’s guest is somebody I’ve been incredibly excited to speak with, Dr Phillip Hay, one of the world’s leading experts in bacterial vaginosis, recurrent thrush, and sexually transmitted infections. He’s a consultant at Guy’s and St. Thomas’ with decades of clinical and academic experience. His work has shaped international guidelines on diagnosing and treating vaginal infections, and he’s at the forefront of research into the vaginal microbiome, especially how we might use new non antibiotic approaches like lactoferrin to treat and prevent BV and thrush. We first connected through our shared interest in women’s health, lactoferrin and microbiome science. In this interview, we’re going to unpack what BV actually is, why it’s so misunderstood, and how it connects to everything from recurrent infections to reproductive health, pregnancy, and even health inequalities. If you’ve ever felt confused or frustrated by the lack of answers when it comes to vaginal health, then this conversation is for you.
Lucy Hope
Good morning, Dr Hay.
Dr Phillip Hay
Thanks, Lucy. I’m always happy to talk about BV. I’ve been known to organise all day seminars.
Lucy Hope
Fantastic. Let’s start with a foundational understanding about BV, bacterial vaginosis, and the vaginal microbiome, for those who aren’t very well informed. For people who’ve heard of BV but don’t quite understand it, what exactly is bacterial vaginosis, and how is it different from, say, thrush or an STI?
Dr Phillip Hay
BV has generally been regarded as an imbalance in the bacteria in the vagina. In health, the vaginal microbiome is dominated by lactobacilli, there are five common species. When you develop BV, the balance shifts and the lactobacilli are overwhelmed by an overgrowth of many bacteria which support each other in a symbiotic community. Perhaps the two most important species are Gardnerella vaginalis and Atopobium vaginae, which some people have recently renamed Fannyhessea.
Lucy Hope
I’d read that, I thought it was quite an amusing renaming.
Dr Phillip Hay
I think it’s a little bit cheeky.
Lucy Hope
So what causes BV? Is it something women can develop spontaneously? Is it something they catch, or a bit of both?
Dr Phillip Hay
When I’m asked if BV is an STI, I tend to sit on the fence and say, sometimes it is and sometimes it isn’t. There are very good studies, particularly from Australia, saying you don’t get BV in virgins. However, even with minimal sexual activity you can start to get BV.
Dr Phillip Hay
Against that, there’s a very old study by an American obstetrician called Bump, always a great name for an obstetrician, who looked at virgin adolescent women and found BV in 12% of them. There’s no doubt BV is at least sexually associated, commoner in women who are sexually active. In women with recurrent BV, if they become sexually inactive, it often becomes less of a problem.
Dr Phillip Hay
Unfortunately, once you’ve been colonised with BV associated bacteria, they can live in the gut and in the womb. You’ve probably got them for life and there’s always a risk of it coming back, whether or not you’re having sex.
Lucy Hope
So that’s probably responsible for the high recurrence rates in BV, is it that once you’ve got, say, Gardnerella, you don’t actually have it until you’re sexually active?
Dr Phillip Hay
There are lots of species being identified, but I think Gardnerella and Atopobium are probably the two key ones. If you look at women who appear to have a healthy lactobacillus dominated flora, molecular tests often show low levels of Gardnerella, Atopobium, Prevotella and other BV associated bacteria as well. There’s always the potential for those to overgrow and relapse into BV.
Lucy Hope
Why might the ecology of the vagina suddenly change in non sexually active women? Can it be triggered by other things?
Dr Phillip Hay
Yes. I wrote a paper 15 to 20 years ago comparing the vagina to life on the seashore. Twelve hours a day you’re underwater, twelve hours a day you’re in blazing sunshine. Over a menstrual cycle you get big differences in pH and in oestrogen levels. Add behavioural factors, washing, douching, sex, STIs, and it’s not surprising it’s a difficult environment for lactobacilli to dominate 100% of the time.
Dr Phillip Hay
There are cyclical changes, diet, and input from the gut as well. Many women with recurrent BV say it comes back with their period, they always say “BV loves blood”. I think the bacteria thrive on the iron from menstrual blood.
Lucy Hope
So blood acts as a food source for those bacteria?
Dr Phillip Hay
Yes. With menstruation, oestrogen levels are low and pH naturally rises. In health the vagina is quite acidic with a pH around 4, with BV it can rise to 5 or 6, which supports growth of BV bacteria.
Lucy Hope
Is there anything women can do around their period to help prevent recurrence, or do they just have to hope they won’t succumb during that time?
Dr Phillip Hay
We’ve long thought that using the combined pill continuously, so you get only two or three breakthrough bleeds a year, reduces exposure to blood and likely reduces BV recurrence. To my knowledge, nobody has done a trial of that, but it makes sense.
Dr Phillip Hay
There was an interesting study in rural Kenya looking at adolescent schoolgirls using menstrual cups, catching the blood rather than letting it flood the vagina. That was associated with a reduction in BV, although there were other behavioural changes (they didn’t need transactional sex to get menstrual products), so there was also a reduction in STIs. You can’t tease out which factor mattered most. Anything that reduces exposure to blood is likely helpful. A footnote, you shouldn’t use menstrual cups if you’ve got a coil, because you might inadvertently pull it out with suction.
Dr Phillip Hay
Other than that, we’re looking at ways to support lactobacilli during menstruation and recovery afterwards, which we’ll come to later.
Lucy Hope
When a woman comes to you with suspected BV or vaginal microbiome dysbiosis, what are the current clinical guidelines for treatment? Is it always antibiotics, or do you ever take a more holistic approach?
Dr Phillip Hay
You treat the symptoms. If we see what looks like BV down the microscope but the woman isn’t reporting symptoms, and particularly after discussing them, there’s no reason to treat. Treating someone today makes very little difference to whether she’ll have it in one or two months’ time. A short course of antibiotics has no long term suppressive effect.
Dr Phillip Hay
Current guidelines still recommend oral metronidazole as first line treatment. I think future generations will say we were mad to use metronidazole for BV. I’m reading papers about a single course of broad spectrum antibiotics or metronidazole disturbing the gut microflora for one to two years. I’m increasingly aware of adverse side effects and breeding resistant bacteria, particularly in the gut microbiome. We need better ways.
Dr Phillip Hay
I’m much more a fan of dequalinium chloride, more an antiseptic than an antibiotic. It’s a licensed treatment for BV, isn’t absorbed into the bloodstream, acts locally in the vagina, and doesn’t upset the rest of the body’s microbiome. It makes far more sense, particularly for recurrent BV, than broad spectrum antibiotics. The only thing holding it back is that it’s a bit more expensive in our cash strapped NHS. It’s also less likely to trigger secondary candida and other problems, so it’s probably still cost effective with a proper evaluation.
Lucy Hope
Since a recent study suggested a male partner can reinfect a woman with recurrent BV, do you prescribe antibiotics for the partner, or is that not adopted in clinical practice?
Dr Phillip Hay
It’s a really interesting area. Many studies have given male partners of women with BV either oral metronidazole, the standard antibiotic for women, or oral clindamycin (an alternative). None showed a significant reduction in relapse rates in the women, although one clindamycin study showed a non significant trend but wasn’t powered to make it significant.
Dr Phillip Hay
I’ve been saying for years that the only intervention reducing the prevalence of BV in women is male circumcision, though there’s unlikely to be wide uptake. A secondary analysis of a study looking at male circumcision to reduce HIV infections in sub Saharan Africa showed a 40% reduction in BV rates in female partners following circumcision.
Dr Phillip Hay
In the recent Australian study, they gave male partners oral metronidazole and clindamycin cream to apply to the glans and under the foreskin (if present) twice a day for seven days, while both partners took metronidazole. There was a 50% reduction in relapse rates in the female partners of treated men. Not a complete cure, there was still 50% relapse at four months, but it’s the first male partner treatment to show a big reduction in rapid relapse. That reflects the observation that if women stop having sex, they often have less of a problem.
Dr Phillip Hay
There’s no doubt these bacteria can live under the foreskin and cause reinfection. Looking back at older (now unethical) studies, Gardner, an American obstetrician who first described what we now call BV, was convinced it was sexually transmitted and caused by Gardnerella. When he infected female volunteers with pure lab grown Gardnerella, only one out of 13 developed BV. But when he used fresh vaginal fluid from someone with BV, nearly all developed BV. So if a male partner harbours BV bacteria under his foreskin and you have unprotected sex, there may be enough bacteria to overwhelm your lactobacilli and trigger BV. It’s not the only route, but certainly one route. I’m interested in whether clindamycin cream alone, without systemic metronidazole, would give similar benefit, avoiding the downsides of antibiotics. That would likely be more acceptable for men as well.
Lucy Hope
Studies suggest BV can raise the risk of other STIs, miscarriage, infertility, preterm birth, and other gynaecological issues. Why is that? What’s happening in the body that gives the microbiome such a wide ranging effect on women’s health?
Dr Phillip Hay
It’s likely that if you’ve got BV in the vagina, you’ve got BV associated bacteria inside the womb in the endometrium, which can have adverse effects in pregnancy. IVF studies show that if you can culture lactobacilli from the catheter used to introduce the embryo, you have a far greater chance of success than if you culture nothing or if you culture Gardnerella or associated bacteria. A Leeds study showed that, following IVF, women with BV had a higher rate of very early pregnancy loss than women without BV in the first two to three weeks after implantation.
Dr Phillip Hay
We’ve long known that women with BV have an increased rate of infection mediated spontaneous preterm birth. The bacteria in the womb grow into the membranes around the baby and cause inflammation. Ultimately they can enter the amniotic fluid, causing infection, and from there enter the foetal lungs, causing foetal sepsis and, in the worst case, intrauterine death. BV is linked with second trimester miscarriage and spontaneous preterm birth. Another bacterium, not specifically related to BV, Ureaplasma, is also implicated.
Dr Phillip Hay
Unfortunately, antibiotic trials treating pregnant women for either Ureaplasma or BV haven’t consistently reduced preterm birth rates, although a study we did in South London using clindamycin did show a reduction in both late miscarriage and preterm birth. Reasons include, antibiotics may not kill all the bacteria involved, treatment may initially trigger more inflammation, and there are concerns about effects of antibiotics in pregnancy on the neonatal gut.
Dr Phillip Hay
I regard our clindamycin study as proof of concept that it’s possible to intervene against ascending infection in pregnancy. But the last thing I want is 15 to 20% of pregnant women treated with clindamycin, you’d soon have antimicrobial resistance and risk a severe gut infection, Clostridioides difficile. You’d rapidly find your neonatal unit full of spores, which would be a major problem. We need a more gentle, physiological way of intervening in pregnancy, not blunderbuss antibiotics.
Lucy Hope
Are women screened for BV when they become pregnant? Is that part of the process?
Dr Phillip Hay
No, because we haven’t consistently shown an intervention that improves pregnancy outcomes. In our study, 83% of women with BV had a normal term birth compared to 91% of those we treated, so the majority will still be fine.
Lucy Hope
I’ve read that a high proportion of women with BV are asymptomatic, anywhere between 50% and 80%. Given potential risks, infertility, miscarriage, preterm birth, should we screen more widely for vaginal microbiome issues?
Dr Phillip Hay
The consistently strong relationships are with preterm birth, late miscarriage, and post termination of pregnancy infection. There is a case for screening and treating women before a termination, at least a surgical one. The other associations are more tenuous. For anyone with infertility going for IVF, it’s very much in their favour to optimise the vaginal microbiome to a lactobacillus dominated flora, it’s certainly something I’d want to do.
Dr Phillip Hay
You might think we should screen widely, but we need an effective intervention that reduces long term relapse. As I said, treating today makes little difference to whether you’ll have BV next month or in two months. If we had more effective interventions, then yes, screening would be worthwhile. There’s also the argument that if it genuinely isn’t bothering someone, why look for it, tell them they’ve got it, and make them worry when we don’t yet have brilliant interventions.
Lucy Hope
If a woman suspects she has BV and has symptoms, what should she do first, GP, GUM clinic, or try something over the counter?
Dr Phillip Hay
GPs generally treat on symptoms, so you might not get a definitive diagnosis, if it’s recurrent, they may send a swab to the lab. The beauty of a sexual health (GUM) clinic is microscopy on the spot, you can have a confirmed or alternative diagnosis and same day treatment. Most gynaecologists, except in private practice, aren’t accessible rapidly in the UK. Home STI kits don’t currently include tests for trichomonas, BV, or thrush, so you won’t get a diagnosis of a vaginal infection from those.
Dr Phillip Hay
Another point, although classically the symptoms of thrush and BV are different, there’s a lot of blurring when you talk to patients. It’s difficult to make a definitive diagnosis on symptoms alone. Trichomonas can share features of thrush (soreness and irritation) and BV (fishy smelling watery discharge). It’s always one to look out for.
Dr Phillip Hay
So yes, the best option with definite symptoms is to go to a sexual health clinic.
Lucy Hope
Do you have advice for women who know they’ve got BV or are struggling with recurrence and are nervous about repeated antibiotic use?
Dr Phillip Hay
I think it’s madness to have repeated courses of metronidazole, it does a lot of harm. I’ve seen several women with recurrent BV who developed irritable bowel syndrome because their microbiome was upset by repeated antibiotics.
Dr Phillip Hay
You can buy pH tests (about £10) that claim to differentiate between BV and thrush. I don’t think they’re much better than a simple pH test and they’re a bit of a waste of money, you’re better off getting a definitive diagnosis.
Dr Phillip Hay
From a chemist, probiotics are of variable quality. Generally, taking an oral probiotic doesn’t deliver enough to the lower gut and vagina to have much effect. Studies show modest benefits, perhaps 20% of women respond, 80% don’t. If probiotics help you, fine, if not, don’t keep wasting your money. Lactic acid gels (for example, Balance Active) certainly reduce symptoms by rapidly lowering pH and smell. But in women with very frequent severe BV who used it daily and took swabs, most reverted to an intermediate flora (not quite BV), and once they stopped after a week, they relapsed to full BV. A randomised trial compared it with metronidazole, about 20% clearance with Balance Active, very similar to spontaneous clearance on placebo. Not very different to no treatment, though it reduces symptoms. If it benefits you beyond the week of use, fine, it’s not an antibiotic and unlikely to harm the rest of your body.
Lucy Hope
Is there a difference between vaginal probiotics and oral supplements? Does enteric coating matter, and should we look for specific strains like Lactobacillus crispatus?
Dr Phillip Hay
One of the best studies used Lactin V, Lactobacillus crispatus, developed in the US by Sharon Hillier. As far as I know it isn’t marketed in the UK, it is available in the US. I have one patient who accessed it there. Gregor Reid has worked for years on combinations such as Lactobacillus rhamnosus with another strain, there’s research behind it. They’re not the primary vaginal strains, but they help a proportion of women, not all. There’s another preparation in Europe that contains a little oestrogen as well, we know oestrogen supports a lactobacillus flora, and again there’s modest improvement.
Lucy Hope
You’re leading research on lactoferrin as a natural, non antibiotic alternative for BV and thrush. How does lactoferrin work in the vagina, and what makes it promising?
Dr Phillip Hay
Lactoferrin has its own world conference annually and has been studied in cancer, infection, and more. It’s a protein we produce in secretions, saliva, tears, gut, vagina, with antimicrobial and anti inflammatory properties. One main mode of action is binding iron, making it unavailable for bacteria and fungi. As I said, BV loves blood and iron, critical in BV development.
Dr Phillip Hay
In evolutionary terms there’s an arms race. While we produce lactoferrin, Gardnerella and other BV associated bacteria produce siderophores which break open human lactoferrin and steal the iron back. Human lactoferrin isn’t terribly effective against BV or candida, although levels rise during infection.
Dr Phillip Hay
Beyond iron binding, lactoferrin may directly kill bacteria and fungi and decrease inflammation. We’re planning to study bovine lactoferrin, extracted from cow’s milk. There’s a 30% difference in molecular sequence from human lactoferrin, in vitro, the siderophores of Gardnerella and those used by candida can’t break open bovine lactoferrin. Once the iron is bound, it’s not accessible. Our preliminary work shows it’s potent against candida in vitro. It’s harder to test Gardnerella, because you must add iron to culture media and the physiological amount is tricky to set.
Dr Phillip Hay
A notable fact, almost uniquely in the human microbiome, lactobacilli don’t use iron in their essential redox enzymes, they use manganese. That’s one reason lactoferrin supports lactobacilli, they don’t need the iron almost every other vaginal bacterium needs.
Dr Phillip Hay
We’re going to run a preliminary study looking at lactoferrin as a potential treatment for BV and candida. It’s not as rapidly potent as an antibiotic, it’s more of a slow burner, so we’re giving it for three weeks to assess effect.
Lucy Hope
Would lactoferrin also have a preventative effect, giving women more options to proactively manage vaginal health?
Dr Phillip Hay
Given it’s not as rapidly potent as an antibiotic, it may have more of a place as a supportive, preventive treatment rather than an acute treatment. There are ongoing studies in that role, including ours.
Dr Phillip Hay
There’s also a fascinating Italian study looking at preventing preterm birth, supporting restoration of a healthy lactobacillus flora and reducing inflammation. In women with shortening cervixes (a precursor to preterm birth), lactoferrin reduced inflammatory mediators, remarkably, cervixes in the lactoferrin group started elongating again, whereas controls continued shortening. It’s potentially very exciting, particularly for preventing pregnancy related complications. The human version likely wouldn’t do much, bovine appears more effective here.
Lucy Hope
I want to run a few myths and remedies past you and ask for a score out of 10 (0 equals absolutely not, 10 equals strong evidence).
• Probiotic vaginal suppositories
Dr Phillip Hay: Six. There are ones in development with teams of lactobacilli rather than just one. I hope they’ll be a nine, let’s wait and see.
• Douching
Dr Phillip Hay: Zero. Every paper associates BV with douching, though some of that may be chicken and egg, if I woke with a horrible smell, I’d want to wash it out. Repeated douching isn’t good, it washes out the good guys as well as the bad.
• Boric acid
Dr Phillip Hay: A cautious seven. It’s an interesting ancient remedy. Potentially harmful in pregnancy, so you can’t take it if you’re at risk of pregnancy or trying to get pregnant. It’s my go to for highly resistant candida where nothing else is working. And it tends to work very well. However, because of the potential harmful effects in pregnancy and no long term toxicity data, I’m very wary of using too much for too long. And also with BV, whilst it can initially be helpful, it seems resistance can develop relatively rapidly if you’re just using boric acid as well. So for that reason, I don’t commonly advocate it as a BV treatment. I think Boots are selling a preparation which contains 20 milligrams of boric acid and they say it’s a treatment for both BV and thrush, whereas the standard dose that we’re using it for thrush is 600 milligrams. So it’s almost homeopathic dose that they’re selling.
• Switching to organic cotton underwear
Dr Phillip Hay: No randomised trials, but it makes sense.
• Letting things “air out” overnight (no underwear or pyjamas)
Dr Phillip Hay: Five, no evidence, it’s just supposition.
• Menstrual cups
Dr Phillip Hay: Limited data, one study I’m aware of, so seven. (Avoid with a coil due to suction.)
• Standard tampons
Dr Phillip Hay: Neither here nor there, three.
• Coconut oil
Dr Phillip Hay: No clinical data that I’m aware of. I’ve seen a little bit of, I think, in vitro data. So I’ll give that a three as well.
• MCT oil
Dr Phillip Hay: Not that I’ve seen.
• Eating more garlic
Dr Phillip Hay: One. It may stop you having sex, of course, but I don’t think there’s any evidence of efficacy.
• Applying Greek yoghurt to the vulva
Dr Phillip Hay: Some women report relief from that, maybe more in terms of thrush than BV, but I think I’ll give that a two as well.
• Drinking cranberry juice
Dr Phillip Hay: Again, there’s some data saying that it helps to stop bad guys from binding to the epithelial cells, but when they did randomised trials in recurrent urinary tract infection, there was no benefit. So again, I’ll give that a one.
• Tea tree oil
Dr Phillip Hay: That’s a difficult one. Again, I’ve not seen any data. I’ve had one patient who swore it got rid of her BV. I’ve used tea tree oil to treat a minor impetigo on my face and it was highly astringent. And I imagine it’d be very painful to put it onto your vagina. So I don’t know if it can come in a very dilute preparation or whatever, but I think I’ll give that a one as well.
• Scented vaginal washes
Dr Phillip Hay: Really bad, zero. You don’t want to be putting complex organic chemicals there if you don’t have to.
• Oral lactoferrin supplements
Dr Phillip Hay: Two. If you had a really good enteric coated one that would genuinely pass through the stomach without getting destroyed, it could be quite helpful. Again, there’s not a lot of data on it, so maybe I’ll give it a five, as might be promising. As long as you get the enteric coating right.