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Groundbreaking clinical study, VIBRANT, signals a new direction for Bacterial Vaginosis (BV) treatment.

A new clinical study published in Cell Host & Microbe is offering a long-awaited shift in how bacterial vaginosis (BV) – one of the most common infections affecting women worldwide – may be treated. Known as the VIBRANT trial, the research moves beyond decades of antibiotic-only approaches, instead focusing on restoring the vaginal microbiome to support longer-term health.

For over 40 years, BV treatment has remained largely unchanged, relying on the same two classes of antibiotics. While these can clear symptoms in the short term, recurrence remains a major challenge, with up to 50–60% of women experiencing a return of infection within months. This reflects a deeper issue: while antibiotics eliminate harmful bacteria, they do not reliably restore the protective bacteria needed to maintain a healthy vaginal environment.

 

A new Approach: Rebuilding, not just Removing

The VIBRANT study, a Phase 1 clinical trial, tested an early-stage live biotherapeutic product candidate designed to restore beneficial bacteria after antibiotic treatment. Specifically, the intervention delivers multiple strains of Lactobacillus crispatus – bacteria commonly found in healthy vaginal microbiomes – giving protective microbes the opportunity to re-establish, take hold, and persist.

Unlike traditional treatments that focus solely on eliminating infection, this approach aims to rebuild what BV removes. The candidate formulations were developed using vaginal L. crispatus strains isolated from women in both South Africa and the United States, ensuring representation of microbial diversity across populations.

Researchers from the Centre for Epidemic Response and Innovation (CERI) at Stellenbosch University played a central role in the study. Prof Jo-Ann Passmore led earlier work isolating and characterising more than 20 South African Lactobacillus strains, while Prof Lenine Liebenberg led analyses examining how the intervention influences inflammation in the genital tract.

“By monitoring inflammatory cytokines in vaginal fluid over time, we can determine if introducing beneficial bacteria like L. crispatus promotes a shift towards a more favourable, less inflammatory state,” said Prof Liebenberg. “The early findings are encouraging.”

 

What the Study Found

The trial included participants at sites in both South Africa and the United States. After receiving standard antibiotic treatment (metronidazole), participants were given either a placebo or one of four live biotherapeutic product candidate regimens for seven days.

The results showed:

• The candidates were safe and well tolerated.
• 66% of participants receiving the live biotherapeutic candidate showed colonisation by at least one beneficial strain within five weeks.
• Among those who initially colonised, 49% remained colonised 10 weeks later – despite treatment lasting only one week.
• Colonisation patterns were consistent across both study sites, suggesting broader applicability across populations.

While these findings do not yet demonstrate prevention of BV recurrence, they provide important early evidence that beneficial vaginal bacteria can successfully establish and persist after treatment.

 

Why This Matters

BV is a highly prevalent yet often under-recognised condition, affecting an estimated one in two women of reproductive age globally. Beyond discomfort, it is associated with increased susceptibility to sexually transmitted infections, including HIV, as well as adverse pregnancy outcomes such as miscarriage and preterm birth.

If future studies confirm that microbiome-based therapies can reduce recurrence, this approach could represent the first major advancement in BV treatment in decades – offering longer-lasting protection, improving reproductive health outcomes, and reducing infection risk globally.

 

Built through Global Vollaboration – and Grounded in Africa

The VIBRANT study reflects a large-scale international collaboration involving institutions across South Africa, the United States, and Europe, including Stellenbosch University, the University of Cape Town, CAPRISA, Harvard Medical School, and others. The work builds on years of research through the Vaginal Microbiome Research Consortium and was supported by the Gates Foundation.

Importantly, the study also reflects a shift in how global health research is conducted. Rather than being tested on African populations, the science was built with African women and grounded in African microbial data – ensuring relevance, representation, and equity in innovation.

As Prof Tulio de Oliveira, Director of CERI, notes: “This study shows how scientific collaboration across continents can generate new solutions to long-standing health challenges. It also reflects the growing leadership of African scientists in microbiome research.”

 

Looking Ahead

With safety established and early signs of durable colonisation observed, researchers are now planning further early-phase studies to better understand how these multi-strain L. crispatus live biotherapeutic candidates may reduce BV recurrence and support long-term vaginal health.

If successful, this approach could mark a milestone in women’s health – addressing a condition that has long needed new tools, new research, and new hope.

 

Full publication: https://www.cell.com/cell-host-microbe/abstract/S1931-3128(26)00084-3  

Text: CERI Media

News date: 2026-04-09

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