The sexually transmitted infection gonorrhoea is a global public health concern, with ~100 million cases per year and increasing difficulty in treating infections caused by multi-drug resistant strains of Neisseria gonorrhoeae. If left untreated, infection can lead to severe sequelae such as adverse pregnancy outcomes and infertility. Vaccine development for gonorrhoea has been challenging due to the antigen variability of the bacteria, the lack of a protective immune response following infection and the absence of an appropriate animal model that mimics infection. We are now investigating novel gonorrhoea vaccine candidates and are evaluating the potential cross-protection of a vaccine that is licensed for the closely related bacteria Neisseria meningitidis.
We have identified and characterised several gonorrhoea vaccine candidates that we are evaluating to identify an optimal multicomponent gonorrhoea vaccine formulation. These antigens are conserved in diverse N. gonorrhoeae strains, are immunogenic, and induce antibodies in mice that are able to kill N. gonorrhoeae via serum bactericidal and/or opsonophagocytic activity, and that are able to block antigen function.
Observational and epidemiological studies have shown that people vaccinated with N. meningitidis serogroup B vaccines (MeNZB or 4CMenB) have a reduced rate of Ng infection compared to unvaccinated controls. We are now conducting a randomised control trial with a 4CMenB to determine if it provides protection against N. gonorrhoeae and to characterise vaccine-induced immune responses.