Investigating Gender and Sex Differences in Immune Responses Through Vaccination of Transgender and Cisgender Persons

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.

NCT Number	NCT06832514
Lead Sponsor	University Ghent Collaborators: University Hospital, Ghent, Centre for Vaccinology - CEVAC
Conditions	Meningococcal Meningitis, Serogroup B, Transgender Persons, Sex Differences in Immune Response, Vaccination
Enrollment	250 participants
Start Date	2025-01-31
Primary Completion	2026-07-31 (estimated)
Study Completion	2026-12-31 (estimated)
Updated on ClinicalTrials.gov	2026-01-20