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NCT Number: NCT06912126

The Maggie Project: Exploring the Origin and Heredity of the Vaginal Microbiome

The vaginal microbiome plays a crucial role in women's health and reproduction, impacting not only women but also their partners and children. However, its ecology and primary colonizers are not well understood. This study aims to explore the origin and heredity of the vaginal microbiome using a citizen science approach. The researchers will assemble a cohort of 100 networks, each with a central participant and 2 to 15 co-participants, totaling up to 500 participants. Participants will provide vaginal or penis swabs, complete questionnaires, and central participants will also donate stool samples. Girls under 18 may participate as co-participants if their mothers are enrolled, with first-void urine samples as an alternative method. Male partners can be included if they have intimate contact with central participants, but male family members and friends will not be part of the study. In the first phase, shared microbial strains along the gut-vagina axis and within the intimate microbiomes of participants from the same and different networks will be assessed. Transmission pathways will also be examined. Additionally, the metabolic environment in the vagina will be characterized. In the second phase, central participants will self-collect weekly vaginal swabs at three time points per year over five years. This phase will provide insights into the persistence and stability of the vaginal microbiome and the vaginal metabolic environment. If consent is given, genetic data from metagenomic sequencing will be analyzed to focus on variations related to the colonization, transmission, and persistence of microbial strains. This study will offer valuable insights into the origins, transmission, and long-term dynamics of the vaginal microbiome.

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Key information

Conditions

Vaginal Microbiome

Age range

10 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

of Central Participants:

  • Adults aged 18 and over at the time of enrollment;
  • Sex: Female;
  • Pre-menopausal;
  • Self-reported good health (including the absence of general infection) at the beginning of the study;
  • Living in Belgium;
  • Sufficient knowledge of the Dutch language;
  • Consent form signed;
  • Participating alongside her mother and at least one additional co-participant in the study.

Exclusion criteria

of Central Participants:

  • Current pregnancy or planned pregnancy at the beginning of the study;
  • Current diagnosis of cancer and/or immunosuppressive therapy in the 6 months before the study;
  • Clinically significant abnormalities of the reproductive organs or any other medical condition at the discretion of the principal investigator;
  • Use of oral/vaginal antibiotics/antifungals in the 2 months before the beginning of the study;
  • Use of oral/vaginal pre-, pro-, post- and/or synbiotics in the 2 weeks before the beginning of the study;
  • Vaginal showering during the study;
  • Participation in an intervention study.

Inclusion criteria

of Co-participants:

  • Closely related to or interacting with the central participant of the network at least during the last six months or more before the study, e.g. her mother, aunts, female cousins, sisters, daughters, housemates, partners or close friends;
  • Aged 18 or over at the time of enrollment; OR 10 or over if the co-participant's mother is also participating in the study;
  • Sex: Female; OR male aged 18 and over who is the partner or one of the partners (in case of polygamous relationships) of the central participant;
  • Self-reported good health (including the absence of general infection);
  • Sufficient knowledge of the Dutch language;
  • Consent form signed.

Exclusion criteria

of Co-participants:

  • Use of oral/vaginal antibiotics/antifungals in the 2 months before the study;
  • Parallel participation in an intervention study;
  • Vaginal showering during the study;
  • Clinically significant abnormalities of the reproductive organs or any other medical condition that, in the opinion of the principal investigator, warrants exclusion from the study.

Treatment and study plan

Primary outcomes

  1. Characterizing the origin and transmission of the vaginal microbiome

    Time frame: Up to one year

    After metagenomic shotgun sequencing, bioinformatic tools will be used to analyze taxonomic and functional data. Vaginal and stool metagenomes from central participants will be compared at the species and strain levels, complemented by whole-genome sequencing of bacterial isolates to identify shared strains between the gut and vaginal microbiomes in the central participants. In addition, microbiome profiles from vaginal, penile, and urine samples will also be compared between central participants and their co-participants within networks. This analysis will then be expanded to examine strain transmission across the entire cohort. Statistical analyses will assess strain similarities within networks, across the cohort, and among all participants.

Secondary outcomes

  1. Characterizing the longitudinal stability of the vaginal microbiome

    Time frame: Up to six years

    The longitudinal stability (i.e., persistence) of the vaginal microbiome will be characterized using metagenomic sequencing data from samples collected during Phase II). Specifically, bioinformatics tools will be used to evaluate the persistence of specific microbial strains within each participant's microbiome over time. Stability will be analyzed by comparing strain composition across the different time points. If necessary, strain-specific primers and polymerase chain reaction (PCR) will be used to confirm strain persistence.

  2. Identifying factors associated with the transmission and persistence of the vaginal microbiome

    Time frame: Up to six years

    Questionnaire data and metagenomic data will be integrated to identify factors influencing the transmission and persistence of the vaginal microbiome at the strain level.

  3. Characterizing the vaginal microbiome at the functional level

    Time frame: Up to six years

    Functional profiles will be annotated based on sequencing reads and compared between samples with and without the presence and persistence of shared strains using statistical analyses. Differences in metabolic pathways and microbial functions will be assessed to determine their impact on microbiome composition and stability.

  4. Determining genetic associations with the colonization, persistence and transmission of the vaginal microbiome

    Time frame: Up to six years

    If the participant agrees, human genetic data will be extracted from metagenomic sequences and analyzed using in-house and publicly available pipelines. The focus will be on identifying common genetic variations that may influence the colonization, transmission, and persistence of specific vaginal microbiome strains. Genes and mutations linked to serious diseases will not be analyzed.

  5. Characterizing the determinants of the vaginal microbiome and metabolome

    Time frame: Up to six years

    Metagenomic and metabolomic data will be integrated with questionnaire responses to investigate factors influencing microbial interactions and metabolite production. The analysis will determine whether metabolite production is influenced by (1) stable host factors (e.g., age, smoking status), (2) dynamic host factors (e.g., recent sexual activity, menstrual cycle phase), or (3) microbiome composition (e.g., community state type, eigentaxa abundances). All data will be securely stored with appropriate protections.

Study contacts

Contact information is provided by the study sponsor or research team.

Sarah Lebeer, Professor

CONTACT

[email protected]

+3232653285

Veronique Verhoeven, Professor

CONTACT

[email protected]

+3232652518

Sponsors and collaborators

Lead sponsor

University Hospital, Antwerp

Other

Registry information

Acronym: Maggie

Important dates

Study start
2025
Primary completion
2026
Study completion
2032
First posted
Apr 4, 2025
Registry last updated
Sep 9, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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