Multicentre double-blind randomised placebo-controlled trial evaluating the efficacy of the meningococcal B vaccine, 4CMenB (Bexsero), against <i>Neisseria gonorrhoeae</i> infection in men who have sex with men: the GoGoVax study protocol.

Abstract

Gonorrhoea, the sexually transmissible infection caused by <i>Neisseria gonorrhoeae</i>, has a substantial impact on sexual and reproductive health globally with an estimated 82 million new infections each year worldwide. <i>N. gonorrhoeae</i> antimicrobial resistance continues to escalate, and disease control is largely reliant on effective therapy as there is no proven effective gonococcal vaccine available. However, there is increasing evidence from observational cohort studies that the serogroup B meningococcal vaccine four-component meningitis B vaccine (4CMenB) (Bexsero), licensed to prevent invasive disease caused by <i>Neisseria meningitidis</i>, may provide cross-protection against the closely related bacterium <i>N. gonorrhoeae</i>. This study will evaluate the efficacy of 4CMenB against <i>N. gonorrhoeae</i> infection in men (cis and trans), transwomen and non-binary people who have sex with men (hereafter referred to as GBM+). This is a double-blind, randomised placebo-controlled trial in GBM+, either HIV-negative on pre-exposure prophylaxis against HIV or living with HIV (CD4 count >350 cells/mm³), who have had a diagnosis of gonorrhoea or infectious syphilis in the last 18 months (a key characteristic associated with a high risk of <i>N. gonorrhoeae</i> infection). Participants are randomised 1:1 to receive two doses of 4CMenB or placebo 3 months apart. Participants have 3-monthly visits over 24 months, which include testing for <i>N. gonorrhoeae</i> and other sexually transmissible infections, collection of demographics, sexual behaviour risks and antibiotic use, and collection of research samples for analysis of <i>N. gonorrhoeae</i>-specific systemic and mucosal immune responses. The primary outcome is the incidence of the first episode of <i>N. gonorrhoeae</i> infection, as determined by nucleic acid amplification tests, post month 4. Additional outcomes consider the incidence of symptomatic or asymptomatic <i>N. gonorrhoeae</i> infection at different anatomical sites (ie, urogenital, anorectum or oropharynx), incidence by <i>N. gonorrhoeae</i> genotype and antimicrobial resistance phenotype, and level and functional activity of <i>N. gonorrhoeae</i>-specific antibodies. Ethical approval was obtained from the St Vincent's Hospital Human Research Ethics Committee, St Vincent's Hospital Sydney, NSW, Australia (ref: 2020/ETH01084). Results will be disseminated in peer-reviewed journals and via presentation at national and international conferences. NCT04415424.