In a significant breakthrough for sexual health, new research has uncovered that bacterial vaginosis (BV) is not just a vaginal imbalance but actually a sexually transmitted infection (STI). This discovery, which has the potential to change the way we approach BV treatment, suggests that people with penises may unknowingly be carriers, contributing to the recurring cycles of BV in women. Published on March 6, 2025, by Monash University and Alfred Health, this study challenges long-held assumptions about the condition and could lead to changes in national treatment guidelines.
Understanding Bacterial Vaginosis (BV)
Bacterial vaginosis is a common condition affecting about one-third of women worldwide. For those who have experienced BV, it’s often known for its uncomfortable symptoms, including itching, a “fishy” odor, and irritation. The condition arises when the natural balance of bacteria in the vagina is disrupted, typically due to an overgrowth of harmful “bad” bacteria. While some individuals may remain asymptomatic, for many, the symptoms are disruptive and painful, leading to frequent trips to the doctor.
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In addition to the discomfort, BV can cause more serious complications, such as infertility, premature births, miscarriages, and an increased vulnerability to other STIs. It’s long been believed that BV is mainly caused by an imbalance in the vaginal microbiome, often exacerbated by behaviors like douching, smoking, or multiple sexual partners. However, the recent research has uncovered a crucial missing link: sexual partners with penises.
The Discovery: BV Is an STI Passed Through Penile Partners
The new research, led by Professor Catriona Bradshaw and Dr. Lenka Vodstrcil, has challenged the traditional approach to BV. Historically, BV has been treated as a condition caused by a disruption of the vaginal microbiome, with treatment typically focusing on antibiotics for women alone. However, the new findings suggest that the bacteria responsible for BV can be transmitted between sexual partners—particularly those with penises—thus classifying BV as an STI.
The study followed 164 heterosexual, monogamous couples where one partner had BV. The researchers treated both partners simultaneously, using a combination of oral and topical antibiotics. The results were striking: the recurrence rate of BV was significantly lower in couples who both received treatment. In fact, the study was so successful that it was stopped early when it became apparent that treating both partners halved the recurrence of BV compared to traditional treatments that focused only on women.
This revelation that men can be carriers of the bacteria responsible for BV means that treating only women may not be enough to fully eradicate the infection, leading to frustrating cycles of recurrence. For many women suffering from BV, this discovery could lead to a new and more effective treatment approach.
The Potential Impact on BV Treatment and Prevention
The implications of this study could be far-reaching. Professor Bradshaw explained that the trial opens up exciting new possibilities for preventing BV recurrence. By treating both partners simultaneously, BV cure rates can improve, leading to better long-term outcomes for women. The research also highlights the importance of addressing BV as an STI, shifting the focus from solely treating women to addressing the condition from a more holistic, couple-based perspective.
Previously, studies suggested that men could harbor bacterial species associated with BV on their penile skin or inside the penis. However, earlier trials that included male partners failed to show significant improvements in female partners’ BV outcomes. Professor Bradshaw emphasized that previous studies didn’t adequately clear the bacteria in men, which led to the misconception that sexual transmission wasn’t a factor.
“This trial has shown that reinfection from partners is causing much of the BV recurrence, and provides evidence that BV is in fact an STI,” said Professor Bradshaw.
A Shift in Clinical Practice
As a result of these findings, the Melbourne Sexual Health Centre, where the research was conducted, has already updated its clinical practice to include treating both partners. A new website has been launched to provide information for both health professionals and the public on how to access this combined treatment approach.
Despite the promising results, changes to national and international treatment guidelines are expected to take time. Clare Keogh, a sexual health doctor at SHINE SA, cautioned that more research is needed before official guidelines are revised. “We don’t have enough evidence to change guidelines currently,” she told ABC News, adding that challenges still exist in ensuring compliance, particularly with male partners who are not directly affected by BV symptoms.
Nevertheless, the study’s findings could have a significant impact on how BV is treated in the future, potentially leading to fewer recurrent infections and improved sexual health outcomes for women.
Government Response and the Way Forward
The study has also garnered attention from government officials. Ged Kearney, assistant minister for health and aged care, acknowledged the importance of the research, emphasizing the serious consequences BV can have on women’s health, including early pregnancy loss and premature labor. “It’s critical that we have a more effective way to treat it,” she said.
While the immediate changes in clinical practice are encouraging, it remains to be seen whether broader health guidelines will follow suit. Professor Bradshaw emphasized the importance of providing accessible information to both health professionals and consumers in the meantime, noting that such shifts in national guidelines often take longer to implement.
The Bigger Picture: Redefining Sexual Health Norms
The discovery that BV is an STI challenges traditional thinking about sexual health. It calls for a shift in how we view sexual health as a shared responsibility, highlighting the importance of open communication and mutual care between sexual partners. By treating both partners simultaneously, we may be able to break the cycle of BV recurrence and significantly improve the quality of life for women affected by the condition.
For many women who have struggled with repeated rounds of antibiotics and creams, this new approach offers hope for a more effective solution. It also serves as a reminder that sexual health is a shared responsibility, and treating one partner in isolation may not be enough to address the underlying issue.
Conclusion: A Step Toward Better Sexual Health for All
This groundbreaking research has the potential to revolutionize the treatment of bacterial vaginosis. By recognizing BV as an STI and treating both partners, we could see a dramatic reduction in recurrent infections and a more effective approach to sexual health overall. While changes to health guidelines may take time, this study paves the way for better, more holistic treatments and serves as an important reminder of the need for ongoing education and open conversations about sexual health.
