Vaccination against antibiotic resistant gonorrhoea for men who have sex with men in England: a modelling study

BackgroundGonorrhoea incidence is increasing rapidly: diagnoses in men who have sex with men (MSM) in England increased eight-fold 2008-2017. Concurrently, antibiotic resistance is making treatment more difficult, leading to renewed interest in a gonococcal vaccine. The MeNZB meningococcal B vaccine is partially protective, and several other candidates are in development. We modelled realistic vaccination strategies under various scenarios of antibiotic resistance and vaccine protection level and duration, to assess the impact of vaccination and examine the feasibility of the WHOs target of reducing gonorrhoea incidence by 90% between 2016 and 2030.\n\nMethodsWe fitted a stochastic transmission-dynamic model, incorporating asymptomatic and symptomatic infection and heterogeneous sexual behaviour, to gonorrhoea incidence in MSM in England, 2008-17, using particle Markov Chain Monte Carlo methods. Bayesian forecasting was used to examine future scenarios, including emergence of extensively antibiotic-resistant (ABR) gonorrhoea.\n\nFindingsEven in the worst-case scenario of untreatable infection emerging, the WHO target could be met by vaccinating all MSM attending sexual health clinics with a 53%-protective vaccine lasting for >6 years, or a 70%-protective vaccine lasting >3 years. A vaccine like MeNZB, conferring 30% protection for 2-4 years, could reduce incidence in 2030 by 45% in the worst-case scenario, and by 75% if >70% of ABR gonorrhoea is treatable.\n\nInterpretationOur statistically-rigorous assessment shows that even a partially-protective vaccine, delivered through a practical targeting strategy, could have substantial benefit in reducing gonorrhoea incidence in the context of an epidemic with rising antibiotic resistance.