Invasive Neisseria meningitidis subtype C in gay, bisexual and other men who have sex with men: a systematic review

Introduction Outbreaks of invasive Neisseria meningitidis subtype C in networks of gay, bisexual and other men who have sex with men (MSM) have been reported. We aimed to explore any factors seen in MSM with invasive N.meningitidis subtype C. Method We searched three bibliographical databases for manuscripts written in English exploring at least one factor seen in MSM with invasive N. meningitidis subtype C published up to May 2024. Following an initial search, removal of duplicates and abstract review, two authors independently reviewed full-text manuscripts and performed a risk of bias assessment using the Joanna Briggs Institute toolkit. Narrative data were synthesised to generate themes. Results 16 manuscripts were included in this review from the USA (n=10), Germany (n=2), France (n=2), Canada (n=1) and Italy (n=1) and consisted of nine case series, four cross-sectional studies, two case reports and one case–control study published between 2003 and 2024 involving 236 MSM with invasive N. meningitidis subtype C, of which at least 64 died. We have highlighted some demographic (African-American or Hispanic identity in the USA, living with HIV), behavioural (kissing, sharing drinks, visiting sex-on-premises venues, visiting gay-oriented venues, using websites/mobile phone apps to meet sexual partners, recreational drug use, multiple and non-regular sexual partners) and infection (previous Chlamydia trachomatis, Treponema pallidum, Neisseria gonorrhoeae , Mpox) factors in MSM with invasive N. meningitidis subtype C. Conclusion These data serve as an important resource to inform and target future public health strategies and outbreak control measures for the prevention of invasive N. meningitidis subtype C in MSM. PROSPERO registration number CRD42024543551. All data relevant to the study are included in the article or uploaded as supplementary information.