July 8, 2026

expert reaction to an RCT of the meningococcal B vaccine to prevent gonorrhoea infection in men who have sex with men (MSM)

A randomised controlled trial published in NEJM looks at the meningococcal B vaccine for preventing gonorrhoea in men who have sex with men (MSM). 

Dr Odile Harrison, Associate Professor, Oxford Population Health Infectious Disease Epidemiology Unit, University of Oxford, said:

“’This is an important study for the gonococcal vaccine field. Previous retrospective, observational studies had suggested that meningococcal outer membrane vesicle vaccines such as the MenB 4CMenB vaccine, might provide some protection against gonorrhoea, raising hopes that an already licensed vaccine could help address a growing public health challenge. However, this large, well-conducted randomised controlled trial found no evidence of protection against gonorrhoea in high-risk populations. Importantly, these findings are consistent with those from the earlier ANRS DOXYVAC trial undertaken in France, strengthening the evidence that any protection conferred by 4CMenB against gonorrhoea in high-risk populations is likely to be lower than initially suggested by observational studies. This shows why randomised trials remain essential for evaluating vaccine effectiveness, particularly when earlier evidence comes largely from observational studies.

“These results are particularly relevant given the recent introduction of a targeted UK programme offering 4CMenB to gay, bisexual and other men who have sex with men at increased risk of gonorrhoea. While this study does not in itself influence the value of that programme, it does emphasise the importance of continuing to evaluate its impact through real-world surveillance as new evidence emerges.

“Although these findings are disappointing, they should not be seen as the end of gonococcal vaccine development. Neisseria gonorrhoeae remains a major global public health threat, particularly with the continued emergence of antimicrobial resistance, and an effective vaccine remains a high priority. This study provides an important benchmark for the field and will help guide the development and evaluation of next-generation vaccines specifically designed to prevent gonorrhoea.’”

‘Meningococcal B Vaccine to Prevent Neisseria gonorrhoeae Infection’ by K.L. Seib et al. will be published in NEJM at 22:00 UK time on Wednesday 8^th July, which is when the embargo will lift.

DOI: 10.1056/NEJMoa2516739

Declared interests

Dr Odile Harrison: Dr Harrison is working on the CoIAI programme (Oxford launches major new AI vaccine research program with the Ellison Institute of Technology) but does not have any industry funding.