Scientists have declared that a little-known bacterial condition is in fact a sexually transmitted infection (STI) that millions already have.
Called bacterial vaginosis (BV), the intimate infection is caused by an imbalance in the bacteria that normally live in the vagina, which is often triggered by sex.
Almost a third of British women, about 10million, are thought to have BV, but only half are thought to show any symptoms.
While normally only causing mild issues like unusual vaginal discharge, BV can have serious consequences including an increased risk of infertility, of contracting other more serious STIs, premature births and newborn deaths.
Now, Australian scientists, in what they dubbed a 'revolution', have found a key to bringing the condition under control is men.
BV is routinely treated with antibiotics but can be notoriously difficult to eliminate.
About half of women with the condition see it return just a few months after it was supposedly cured.
But experts at Monash University and Melbourne Sexual Health Centre found that treating BV patients as a couple, as they would with an STI, massively boosted success rates.
In tests on 164 heterosexual couples where a woman had BV, they gave all female patients antibiotics and then randomly assigned their male partners to either also receive medication or not, with the latter group acting as a control.
Comparing results after three months, they found rates of BV returning halved among the couples treated simultaneously compared to those where only the woman received care, the latter approach being the one used for women in Britain.
While previous studies had suggested men could be carrying bacteria that lead to BV, older trials had failed to show treating male partners had any impact on the success of women's treatment.
However, the experts behind the new study used both oral antibiotics and an antibiotic cream, applied to the man's penis, and this combination proved effective
Professor Catriona Bradshaw, an expert in sexual health at Monash, said: 'Our trial has shown that reinfection from partners is causing a lot of the BV recurrence women experience, and provides evidence that BV is in fact an STI.'
This runs counter to advice currently issued by the NHS, which states that BV is not an STI.
The results have been so successful that Melbourne Sexual Health Centre has already made the couple-based treatment for BV part of their standard practice.
Professor Bradshaw added this approach to treating BV could reap great dividends given how easy it was to implement.
'This successful intervention is relatively cheap and short and has the potential for the first time to not only improve BV cure for women, but opens up exciting new opportunities for BV prevention, and prevention of the serious complications associated with BV,' she said.
Medics have previously warned women to take steps to avoid increasing their risk of contracting BV.
These include avoiding using perfumed soaps around the vagina and avoiding douching (cleaning the inside of the vagina with water using a spray).
Other tips include avoiding tight-fitting clothing like lingerie or sweaty gym clothes for long periods as these can create perfect conditions for BV to thrive.
Lastly, they advised using condoms during sex to help protect the bacteria that normally live in the vagina.
