Meningococcal Meningitis, Serogroup BPhase 4VaxxygenderNCT06832514
Investigating Gender and Sex Differences in Immune Responses Through Vaccination of Transgender and Cisgender Persons
A Phase 4 study testing Serogroup B meningococal vaccine in people with Meningococcal Meningitis, Serogroup B and Transgender Persons, run by University Ghent at 1 site in Belgium.
Trial summary
Sexual differences are a well-established source of biological variation in immune system functioning, with men often displaying lower adaptive immune responses (e.g. antibody production) to infections and vaccinations compared to women. Read more about this study
- Who is it for?
- Ages 18 to 50 yearsHealthy volunteers can take part
- Conditions the study is for
- Meningococcal Meningitis, Serogroup B, Transgender Persons, Sex Differences in Immune Response
- What is being tested?
- Serogroup B meningococal vaccine
- Type of treatment
- Vaccines, Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 250 participants
- Where
- 1 siteBelgium
- Study dates
- 31 Jan 2025to 31 Dec 2026
- Phase
- Phase 4
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 50 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Written signed informed consent form (ICF) obtained before any study-related activities.
- Participants aged between, and including, 18 and 50 years of age at the time of signing the ICF which equals with the time of the first study intervention.
- Participants who are considered to be in good general health as determined by the investigator by medical evaluation including medical history andphysical examination at enrollment.
- Participants with a BMI within the range 18.5 to 35 kg/m2 inclusive at screening.
- POCBP (18-50 years of age) who are not pregnant or breastfeeding or planning to become pregnant during the clinical study.
- Transgender persons need to be under stable gender-affirming hormone therapy (GAHT) for at least 6 months. Compliance needs to be documented by hormonal lab tests.
- POCBP must have a negative urine pregnancy test at each vaccination visit (Visit 1 and Visit 5) Refer to Section 8.6.5 for Pregnancy Testing.
- Participants who are willing and able to comply with the study procedures and are capable to comply with the requirements of the protocol (e.g. return for follow-up visits) as determined by the investigator.
Who cannot join
- Current or previous, confirmed or suspected disease caused by N. meningitidis and N. gonnorrhoea.
- Household contact with and/or intimate exposure (e.g. sexual or saliva contact) to an individual with laboratory confirmed N. meningitidis infection during life.
- Transgender persons in a diagnostic phase (no hormonal intervention) or undergoing treatment based on the suppression of endogenic hormones (e.g. gonadotropin releasing hormone analogues).
- Current or previous infection with hepatitis B, hepatitis C or human immunodeficiency virus (HIV) as determined by anamnesis and medical history.
- Past or current confirmed or suspected immune-suppressive or immune-deficient condition, at the discretion of the investigator, including but not limited to blood, endocrine, hepatic, muscular, nervous system or skin autoimmune disorders, lupus erythematosus and associated conditions or disorders (e.g. rheumatoid arthritis, scleroderma) or immunodeficiency syndromes (including, but not limited to: acquired immunodeficiency syndromes and primary immunodeficiency syndromes).
- History of confirmed hypersensitivity, anaphylaxis and/or other severe allergic reactions (e.g., generalized urticaria, angioedema, bronchospasm) to any component of the study vaccine or excipients (sodium chloride, histidine, sucrose, kanamycin and water for injection), medical products, or medical equipment whose use is foreseen in this study, as determined by the investigator.
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- Clinical conditions representing a contraindication for IM administration and blood draws, as judged by the investigator, e.g. thrombocytopenia or history of bleeding disorder (e.g. factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or significant bruising or bleeding difficulties.
- History of asplenia, functional asplenia or any condition resulting in the absence or removal of the spleen.
- Active malignancy or malignancy within the past 5 years that, in the opinion of the investigator, may affect immune response or participant safety - except for localized and fully treated cancers not requiring long-term therapy such as chemotherapy or radiotherapy (e.g. completely resected basal cell carcinoma, cervical intraepithelial neoplasia, melanoma in situ, early-stage thyroid cancer), based on the investigator's clinical judgement.
- History of idiopathic urticaria within the past year.
- Currently pregnant, breast-feeding or planning to become pregnant. Cisgender women with permanent infertility due to an alternate medical cause (e.g. documented bilateral oophorectomy, androgen insensitivity, gonadal dysgenesis) are excluded to participate. For individuals with permanent infertility due to an alternate medical cause other than the above, investigator discretion should be applied to determining study entry. Additionally, cisgender women in a postmenopausal state, defined as no menses for 12 months without an alternative medical cause are also excluded to participate. Refer to
- Any other clinical condition that, in the opinion of the investigator, could compromise the participant's safety and/or compliance with the study protocol (e.g. current or recent (< 1 years ago) heavy smoking (> 20 cigarettes per day) or daily heavy vaping (equivalent to 20 cigarettes), drug- or alcohol (> 15 units for cisgender men and transgender women or > 10 units or cisgender women and transgender men per week) abuse/addiction.
- Behavioral or cognitive impairment, unstable psychiatric conditions (e.g. forced admission, suicidal thoughts in the last two year) or other psychiatric disease that, in the opinion of the investigator, may interfere with study compliance, as well as with the subject's ability and/or safety to participate in the study. Stable psychiatric conditions (e.g. under-controlled depression) will be evaluated based on the investigators judgement.
- Donation of blood or blood products within 90 days prior to the first vaccination visit (Visit 1) until Day 56 (Visit 9).
- Previous vaccination against any group B meningococcal vaccine (Bexsero®, Trumenba®) at any time prior to informed consent.
- Prior receipt of a live-attenuated vaccine in the 28 days prior to administration of the 4CMenB vaccine, within 14 days for subunit or inactivated vaccines or planning to receive a vaccine in between the first and second vaccine administration, as well as 28 days following administration of the second 4CMenB vaccine dose.
- Currently participating in another clinical study, or planning to participate in another study during the study period, or administration of any investigational drug or medical device in the 28 days prior to study vaccination.
- Prior receipt of blood, blood-derived products or immunoglobulins in the 6 months prior to administration of the study vaccine, or planning to receive such product during the study period.
- Chronic administration (defined as 14 consecutive days in total) of immunosuppressants (e.g. corticosteroids (PO/IV/IM) or other immune-modifying drugs (e.g. antineoplastic agents, radiotherapy) during the period starting 90 days prior to vaccination or planned administration during the study (excluding topical, inhaled and intranasal preparations and intra-articular injections). For corticosteroids, this will mean prednisone ≥ 20 mg/day, or equivalent.
- POCBP (cisgender women and transgender men) who use the following contraceptive methods will not be included in the study
- Oral, injectable, intravaginal (i.e. intravaginal ring) or transdermal combined (oestrogen- and progesterone-containing) hormonal contraception associated with inhibition of ovulation.
- Oral, injectable or implantable progestogen-only hormonal contraception associated with inhibition of ovulation.
- Current anti-tuberculosis prophylaxis or therapy.
- 25. Participants with a history of any medical conditions that, in the opinion of the investigator, might interfere with the results of the study or pose additional risk to the participants when participating in the study.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Belgium1 site, 1 recruiting
- Recruiting
CEVAC, University Hospital Ghent, Belgium
Ghent, 9000
Prof. Dr. Isabel Leroux-Roels, PhD, MD, +3293322068, isabel.lerouxroels@uzgent.be
Dr. Valentino D'Onofrio, PhD, +3293322068, valentino.donofrio@uzgent.be
About this study
Official title: An Investigator-initiated, Single-center Academic Study in Healthy Transgender and Cisgender Persons Aged Between 18 and 50 Years to Investigate Gender and Sex Differences in Immune Responses to Meningococcal Serogroup B Vaccination
Sexual differences are a well-established source of biological variation in immune system functioning, with men often displaying lower adaptive immune responses (e.g. antibody production) to infections and vaccinations compared to women. The impact of sex and gender on immune responses and immune functioning warrants more in-depth investigation. This study is an investigator-initiated project aimed at prospectively assessing the immune response towards a vaccine in transgender and cisgender individuals. Transgender individuals retain their chromosomal sex while undergoing a significant hormonal shift that aligns with their experienced gender. Immune responses induced by the four-component meningococcal serogroup B (4CMenB; Bexsero®) vaccine will be evaluated in transgender individuals and compared with responses observed in cisgender individuals. Both humoral and cellular immune responses induced by two doses of the 4CMenB vaccine will be quantified and analysed. This approach is expected to provide new insights into the effects of gender and sex differences on innate and adaptive immune responses.
- Conditions
- Meningococcal Meningitis, Serogroup B, Transgender Persons, Sex Differences in Immune Response, Vaccination
- Being tested
- Serogroup B meningococal vaccine
- Keywords
- Gender
- Medical subject headings
- Meningitis, Meningococcal, Coitus
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Serogroup B meningococal vaccineBiological
Also called Four component meningococcal serogroup B vaccine, 4CMenB, Bexsero
The 4CMenB vaccine will be administered via two intramuscular (IM) injections in the non-dominant upper arm, with a one month interval.
| Study group | Role | What they receive |
|---|---|---|
| 4CMenB vaccination cisgender men | Experimental | The four component meningococcal serogroup B (4CMenB) vaccine will be administered to 30 cisgender men via two intramuscular injections, with a one month interval. Receives: Biological: Serogroup B meningococal vaccine |
| 4CMenB vaccination cisgender women | Experimental | The four component meningococcal serogroup B (4CMenB) vaccine will be administered to 30 cisgender women via two intramuscular injections, with a one month interval. Receives: Biological: Serogroup B meningococal vaccine |
| 4CMenB vaccination transgender women | Experimental | The four component meningococcal serogroup B (4CMenB) vaccine will be administered to 30 transgender women via two intramuscular injections, with a one month interval. Receives: Biological: Serogroup B meningococal vaccine |
| 4CMenB vaccination transgender men | Experimental | The four component meningococcal serogroup B (4CMenB) vaccine will be administered to 30 transgender men via two intramuscular injections, with a one month interval. Receives: Biological: Serogroup B meningococal vaccine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Characterise humoral, adaptive immune responses elicited by two administrations of 4CMenB in transgender and cisgender healthy participants, aged 18 to 50 years.
The human serum bactericidal antibody titers (hSBA) against reference strains for factor H binding protein (fHbp), Neisseria adhesin A (NadA) and Porine A (PorA) in transgender and cisgender participants.
Measured: From the first vaccination visit to two months post-primary vaccination
Secondary outcomes (1)
Characterise the cellular (CD4+ and CD8+ T cell), adaptive immune responses elicited by two administrations of 4CMenB in transgender and cisgender healthy participants, aged 18 to 50 years.
T cell-mediated immune responses in peripheral blood mononuclear cells (PBMCs) collected at different timepoints post-vaccination in 4CMen-B vaccinated transgender and cisgender participants.
Measured: From the first vaccination visit to two months post-primary vaccination
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Feb 2025
- Study start31 Jan 2025
- Primary completion31 Jul 2026 (estimated)
- Study completion31 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Meningococcal Meningitis, Serogroup BStudies of the same condition, open and under way.
- More trials run by University GhentThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Model description
- A total of 250 healthy adults will be recruited, with 120 completing the trial, and divided in the following 4 cohorts, each consisting of 30 healthy adult participants aged 18-50 years (inclusive): * Cohort 1: Transgender men (n=30) * Cohort 2: Transgender women (n=30) * Cohort 3: Cisgender men (n=30) * Cohort 4: Cisgender women (n=30) Each particpant will receive the four-component meningococcal serogroup B (4CMenB, Bexsero) vaccine as two intramuscular doses, with a one month interval.
- Masking
- None (open label)
- Enrolment
- 250 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Ghent
- Sponsor type
- University, hospital or other
- Collaborators
- University Hospital, Ghent, Centre for Vaccinology - CEVAC
- Responsible party
- Sponsor
- Investigators
- Prof. Dr. Isabel Leroux-Roels, PhD, MD, Principal investigator, CEVAC, University Hospital Ghent, Belgium
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06832514
- Sponsor's protocol ID
- ONZ-2024-0461
- Other IDs
- 2024-515599-11-00
- Acronym
- Vaxxygender
- Status last verified
- Jan 2026
- First submitted
- 10 Feb 2025
- Last updated
- 20 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 20 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- An Investigator-initiated, Single-center Academic Study in Healthy Transgender and Cisgender Persons Aged Between 18 and 50 Years to Investigate Gender and Sex Differences in Immune Responses to Meningococcal Serogroup B Vaccination
- ClinicalTrials.gov ID
- NCT06832514
- Acronym / sponsor ID
- Vaxxygender / ONZ-2024-0461
- Conditions
- Meningococcal Meningitis, Serogroup B, Transgender Persons, Sex Differences in Immune Response, Vaccination
- Keywords
- Gender
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 250 participants (estimated)
- Lead sponsor
- University GhentUniversity, hospital or other
- Collaborators
- University Hospital, Ghent, Centre for Vaccinology - CEVAC
- Study start
- 31 Jan 2025 (actual)
- Primary completion
- 31 Jul 2026 (estimated)
- Study completion
- 31 Dec 2026 (estimated)
- First posted
- 18 Feb 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Sexual differences are a well-established source of biological variation in immune system functioning, with men often displaying lower adaptive immune responses (e.g. antibody production) to infections and vaccinations compared to women. The impact of sex and gender on immune responses and immune functioning warrants more in-depth investigation. This study is an investigator-initiated project aimed at prospectively assessing the immune response towards a vaccine in transgender and cisgender individuals. Transgender individuals retain their chromosomal sex while undergoing a significant hormonal shift that aligns with their experienced gender. Immune responses induced by the four-component meningococcal serogroup B (4CMenB; Bexsero®) vaccine will be evaluated in transgender individuals and compared with responses observed in cisgender individuals. Both humoral and cellular immune responses induced by two doses of the 4CMenB vaccine will be quantified and analysed. This approach is expected to provide new insights into the effects of gender and sex differences on innate and adaptive immune responses.
Study design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 4
- Model description
- A total of 250 healthy adults will be recruited, with 120 completing the trial, and divided in the following 4 cohorts, each consisting of 30 healthy adult participants aged 18-50 years (inclusive): * Cohort 1: Transgender men (n=30) * Cohort 2: Transgender women (n=30) * Cohort 3: Cisgender men (n=30) * Cohort 4: Cisgender women (n=30) Each particpant will receive the four-component meningococcal serogroup B (4CMenB, Bexsero) vaccine as two intramuscular doses, with a one month interval.
| Arm | Type | Receives |
|---|---|---|
| 4CMenB vaccination cisgender men | Experimental | Biological: Serogroup B meningococal vaccineThe four component meningococcal serogroup B (4CMenB) vaccine will be administered to 30 cisgender men via two intramuscular injections, with a one month interval. |
| 4CMenB vaccination cisgender women | Experimental | Biological: Serogroup B meningococal vaccineThe four component meningococcal serogroup B (4CMenB) vaccine will be administered to 30 cisgender women via two intramuscular injections, with a one month interval. |
| 4CMenB vaccination transgender women | Experimental | Biological: Serogroup B meningococal vaccineThe four component meningococcal serogroup B (4CMenB) vaccine will be administered to 30 transgender women via two intramuscular injections, with a one month interval. |
| 4CMenB vaccination transgender men | Experimental | Biological: Serogroup B meningococal vaccineThe four component meningococcal serogroup B (4CMenB) vaccine will be administered to 30 transgender men via two intramuscular injections, with a one month interval. |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (8 listed)
- Written signed informed consent form (ICF) obtained before any study-related activities.
- Participants aged between, and including, 18 and 50 years of age at the time of signing the ICF which equals with the time of the first study intervention.
- Participants who are considered to be in good general health as determined by the investigator by medical evaluation including medical history andphysical examination at enrollment.
- Participants with a BMI within the range 18.5 to 35 kg/m2 inclusive at screening.
- POCBP (18-50 years of age) who are not pregnant or breastfeeding or planning to become pregnant during the clinical study.
Key exclusion criteria (24 listed)
- Current or previous, confirmed or suspected disease caused by N. meningitidis and N. gonnorrhoea.
- Household contact with and/or intimate exposure (e.g. sexual or saliva contact) to an individual with laboratory confirmed N. meningitidis infection during life.
- Transgender persons in a diagnostic phase (no hormonal intervention) or undergoing treatment based on the suppression of endogenic hormones (e.g. gonadotropin releasing hormone analogues).
- Current or previous infection with hepatitis B, hepatitis C or human immunodeficiency virus (HIV) as determined by anamnesis and medical history.
- Past or current confirmed or suspected immune-suppressive or immune-deficient condition, at the discretion of the investigator, including but not limited to blood, endocrine, hepatic, muscular, nervous system or skin autoimmune disorders, lupus erythematosus and associated conditions or disorders (e.g. rheumatoid arthritis, scleroderma) or immunodeficiency syndromes (including, but not limited to: acquired immunodeficiency syndromes and primary immunodeficiency syndromes).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Serogroup B meningococal vaccineAlso: Four component meningococcal serogroup B vaccine, 4CMenB, BexseroThe 4CMenB vaccine will be administered via two intramuscular (IM) injections in the non-dominant upper arm, with a one month interval. | Biological | 4CMenB vaccination cisgender men, 4CMenB vaccination cisgender women, 4CMenB vaccination transgender men, 4CMenB vaccination transgender women |
Primary outcome
Characterise humoral, adaptive immune responses elicited by two administrations of 4CMenB in transgender and cisgender healthy participants, aged 18 to 50 years.
Time frame: From the first vaccination visit to two months post-primary vaccination
The human serum bactericidal antibody titers (hSBA) against reference strains for factor H binding protein (fHbp), Neisseria adhesin A (NadA) and Porine A (PorA) in transgender and cisgender participants.
1 secondary outcome
Characterise the cellular (CD4+ and CD8+ T cell), adaptive immune responses elicited by two administrations of 4CMenB in transgender and cisgender healthy participants, aged 18 to 50 years.
Time frame: From the first vaccination visit to two months post-primary vaccination
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Jan 2026.
- Individual participant dataSharing planned: No
Related trials for Meningococcal Meningitis, Serogroup B
Active, not recruitingPhase 4
A Study on the Immune Response and Safety of a Vaccine Against N. Meningitidis Serogroup B Infection in Healthy Infants From 2 Months of Age
Meningitis, Meningococcal
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Prof. Dr. Isabel Leroux-Roels, PhD, MD principal investigator
CEVAC, University Hospital Ghent, Belgium
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Serogroup B meningococal vaccine in people with Meningococcal Meningitis, Serogroup B and Transgender Persons, run by University Ghent at 1 site in Belgium.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 24 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 20 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Belgium. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Prof. Dr. Isabel Leroux-Roels, PhD, MD (+3293322068, isabel.lerouxroels@uzgent.be), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Characterise humoral, adaptive immune responses elicited by two administrations of 4CMenB in transgender and cisgender healthy participants, aged 18 to 50 years. (time frame: From the first vaccination visit to two months post-primary vaccination). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Jan 2026.