Flashtalk 25th International Pathogenic Neisseria Conference 2026

Modelling the impact of introducing the 4CMenB vaccine to Australian adolescents on Neisseria gonorrhoeae transmission (#039)

Ben B Hui 1 , Bing Wang 2 3 , Kate L Seib 4 , James Ward 5 , John Kaldor 1 , Richard Gray 1 , Helen Marshall 2 3
  1. The Kirby Institute, UNSW Sydney, Sydney, NSW, Australia
  2. Department of Paediatrics, Women’s and Children’s Health Network, North Adelaide, South Australia, Australia
  3. Robinson Research Institute and School of Medicine, College of Health, Adelaide University, Adelaide, South Australia, Australia
  4. Institute for Biomedicine and Glycomics, Griffith University, Gold Coast, Queensland, Australia
  5. The Poche Centre for Indigenous Health, University of Queensland, Brisbane, Queensland, Australia

Heterosexually transmitted Neisseria gonorrhoeae (NG) infection in Australia is most prevalent among adolescents and young adults. Furthermore, of gonorrhoea notifications reported in 2024 in the 15–19-year age group, 49% were among Aboriginal and Torres Strait Islander people. Several observational studies have suggested the 4CMenB vaccine, which is approved for protection against meningococcal B infection, may also confer moderate cross-protection against NG infection for approximately 4–5 years when administered to adolescents. In this infectious disease modelling study, we investigated the optimal timing of vaccination under the assumption of moderate protection against NG among young Australians.

We developed an individual-based model of NG transmission among the heterosexual population of Australia aged 15-40 years, stratified by gender, age, Aboriginal and Torres Strait Islander status, and remoteness of residence. The model was calibrated to notification data for urban, regional, and remote Aboriginal and Torres Strait Islander and non-Indigenous populations. Simulations of vaccination roll-out strategies for 15-19-year-olds (reflecting school-based programs) were conducted to estimate the impact on NG prevalence in the overall population aged 15-40.

Achieving 75% vaccine coverage consistently across the target age group is projected to reduce overall NG prevalence by 18% five years after implementation. This includes a 14% reduction among individuals aged 15-19 years and a 12% reduction among Aboriginal and Torres Strait Islander in remote populations. Increasing coverage to 90% further reduces overall NG prevalence by 20%, whereas a lower coverage level of 50% yields a 13% reduction.

Despite only moderate effectiveness and waning protection beyond adolescence, the 4CMenB vaccine could reduce NG prevalence at the population level. These reductions require a high uptake of vaccine among adolescents which could be achieved through a school-based vaccination program.