Public health impact and cost-effectiveness of gonorrhoea vaccination: an integrated transmission-dynamic health-economic modelling analysis

Background Gonorrhoea is a rapidly-growing public health threat, with rising incidence and increasing drug-resistance. Evidence that meningococcal vaccines MeNZB and 4CMenB offer protection has created interest in using 4CMenB against gonorrhoea and in developing gonorrhoea-specific vaccines, but cost-effectiveness and how efficacy and duration of protection affect a vaccine’s value have not been assessed. Methods We developed an integrated transmission-dynamic health-economic model, calibrated using Bayesian methods to surveillance data (GUMCAD: Genitourinary Medicine Clinic Activity Dataset, and GRASP: Gonococcal Resistance to Antimicrobials Surveillance Programme) on menwho-have-sex-with-men (MSM) in England. We considered vaccination of MSM from the perspective of sexual health clinics (with and without vaccination of all adolescents in schools), comparing three realistic approaches to targeting: vaccination-on-attendance for testing; vaccination-on-diagnosis with gonorrhoea; or vaccination-according-to-risk, offered to patients diagnosed with gonorrhoea plus those testing negative who report high numbers of partners (>5p.a.). We varied vaccine uptake (0·5-2× HPV vaccine uptake); efficacy (1-100%) and duration of protection (1-20 years); future epidemic trajectories (current trends stabilising, or continuing); and the time-horizon considered (10&20 years). Findings Adolescent vaccination has little impact with only 1·7%p.a. vaccinated. Vaccinationaccording-to-risk combines high impact and efficiency: even under conservative assumptions 4CMenB would likely be cost-saving in use against gonorrhoea in MSM in England at the current NHS price for use against infant meningitis, averting an estimated mean 110,200(95%CrI:36,500- 223,600) cases, gaining 100·3(31·0-215·8) QALYs, and saving £7·9M(£0·0M-£20·5M) over 10 years. A hypothetical gonorrhoea vaccine’s value is increased more by improving its efficacy than its duration of protection: e.g. 30% protection lasting 2 years has a median value of £48(95%CrI:£22-£85) per dose (over 10 years with a QALY valued at £20,000); doubling efficacy or duration of protection increases the value to £102(£53-£144) or £72(£34-£120), respectively. Interpretation We recommend vaccination-according-to-risk of MSM in sexual health clinics in England with 4CMenB be considered. Development of gonorrhoea-specific vaccines should prioritise maximising efficacy over duration of protection