Bacterial vaginosis (BV) is a common condition characterized by an overgrowth of pathogenic bacteria in the vaginal microbiome. While traditionally not considered a serious health issue, a groundbreaking new study has sparked a debate among researchers about whether BV should be categorized similarly to sexually transmitted infections (STIs).

According to research, approximately 25% to 35% of individuals with vaginas will experience bacterial vaginosis at some point in their lives. This condition arises when there is an imbalance in the microbial population of the vagina, leading to a dominance of harmful bacteria over beneficial strains. Though it typically does not lead to severe complications, it does increase susceptibility to other STIs, including HIV. This connection has prompted some experts to argue that BV treatment protocols should be reevaluated to reflect its similarities with STIs.

Joining me today are two leading researchers in the field: Lenka Vodstrcil, a senior research fellow at Monash University's Melbourne Sexual Health Center, and Catriona Bradshaw, a professor of sexual health medicine at Monash University and Alfred Hospital. Theyve been instrumental in advancing our understanding of BV and its implications for sexual health.

Before we delve into their findings, it's important to clarify that BV can be diagnosed in individuals who have no sexual history, as it is an imbalance of vaginal bacteria rather than a strict infectious disease. The aim of the current research is not to determine how individuals initially acquire BV, but rather how potential transmission between partners could complicate treatment outcomes.

So, Cat, can you explain what exactly bacterial vaginosis is?

Catriona Bradshaw: Certainly! Bacterial vaginosis is primarily a disorder of the vaginal microbiome, or more specifically, a dysbiosis. In a healthy vaginal microbiome, the presence of lactobacilli bacteria helps maintain a low pH level and restrict bacterial diversity. However, with BV, these beneficial bacteria diminish, allowing various other bacteria to proliferate. This shift not only causes a distinct odor but also results in the formation of a biofilma protective layer that these harmful bacteria create to shield themselves from both the body's immune responses and antibiotic treatments. This leads to the characteristic discharge associated with BV.

Despite extensive research, we have yet to identify a single infectious agent responsible for BV. It presents as a polymicrobial infection; in other words, it involves multiple organisms. Current estimations suggest that BV affects nearly one in four women worldwide.

Feltman: Your recent study suggests that BV may be treated like an STI. Can you elaborate on how you reached this conclusion?

Bradshaw: Our research indicates a strong association between BV acquisition and exposure to new sexual partners. Studies reveal that individuals who do not use condoms are at a higher risk of developing BV, and its incubation period mirrors that of bacterial STIs, typically spanning three to four days. Alarmingly, when treated, the recurrence rate of BV is exceedingly highover 50% within three months, escalating to between 60% and 80% among individuals with regular sexual partners. This suggests a reinfection pattern that is reminiscent of other STIs. Historically, treatment strategies have focused solely on women, but our findings indicate that neglecting partner treatment could be a significant factor in BV recurrence.

Feltman: Lenka, can you describe the methodology of your study and how you demonstrated BVs STI-like profile?

Lenka Vodstrcil: Of course! We conducted multiple studies over several years to build our evidence base. We revisited the concept of partner treatment, considering previous trials from the 1980s and 1990s that yielded limited success. However, a pivotal review in 2012 indicated that the results from those earlier trials should not dismiss the possibility of sexual transmission. Notably, we discovered through genetic sequencing that the bacteria associated with BV also reside in the male urethra and on the penile skin. Consequently, we chose to implement a dual-therapy approach targeting both sites. In our clinical trial, we treated both members of heteronormative couples simultaneously, which resulted in significantly improved outcomes for women.

Feltman: Theres often controversy surrounding the classification of certain conditions as STIs due to the stigma involved. Did you face any backlash when proposing that BV might be labeled as such?

Bradshaw: Undoubtedly, this is a sensitive topic. While its crucial to acknowledge the distress that BV causes for many womenimpacting their relationships and overall quality of lifethere is a hesitance to label it as an STI. We believe it's paramount to inform women and their partners about the sexual transmission aspect of BV. Not doing so can result in frustration and distress, as women often cycle through antibiotics without understanding the broader implications of BV. Our research has shown that BV is indeed associated with increased risks for STIs and complications such as preterm birth and miscarriage. Thus, while the term may carry stigma, we believe its essential to address it candidly to promote awareness and encourage prevention.

Feltman: What are the outstanding questions we still have regarding BV that need to be explored further?

Vodstrcil: A significant mystery remains: we still do not know the fundamental cause of BV. Is there a particular organism that must be present to initiate the infection? Additionally, we need to develop more effective treatments for persistent biofilms, which could enhance diagnostic capabilities and lead to more targeted therapies. We are also investigating whether specific organisms can be sexually transmitted between partners, which could further aid in developing preventative strategies. It's worth noting that while our study focused on heterosexual relationships, we recognize that women and gender-diverse individuals can also carry BV-causing bacteria, underscoring the need for inclusive treatment guidelines.

Bradshaw: Theres a substantial paradigm shift in clinical practice that needs to occur. We have created a dedicated website at the Melbourne Sexual Health Center to provide accessible resources for patients and healthcare professionals, including animations and treatment instructions. Our goal is to make this information as straightforward and widely available as possible to help everyone involved.

Feltman: I appreciate you both taking the time to discuss these critical issues. Your insights are invaluable for our audience.

Vodstrcil: Thank you for having us.

Bradshaw: Yes, thank you. Its been a pleasure to share our work with you.

Feltman: That brings us to the end of todays episode. Well return on Friday with an intriguing story about how certain prenatal tests can inadvertently detect cancer in pregnant individuals. Science Quickly is produced by Rachel Feltman, Fonda Mwangi, Kelso Harper, Naeem Amarsy, and Jeff DelViscio, with editing by Alex Sugiura. Our theme music is composed by Dominic Smith. For more in-depth science news, subscribe to Scientific American. Until next time!