The Impact of Introducing Meningococcal C/ACWY Booster Vaccination among Adolescents in Germany: a Dynamic Transmission Modelling Study

Background: In Germany, primary vaccination against invasive meningococcal disease (IMD) serogroup C aims to reduce the highest burden of IMD in infants aged 12-23 month. Due to another IMD-peak in adolescents, we modelled the potential impact of introducing adolescent boosters with conjugate meningococcal C or ACWY (MenC/MenACWY) vaccines. Methods: We built an age- and serogroup-structured dynamic-transmission model for Germany, which we calibrated to national surveillance data in 2005-2019. We simulated five vaccination scenarios of either continuing with the current MenC primary vaccination (scenario 1), or additionally introducing MenC or MenACWY boosters at age 13 years (scenarios 2-3) or 16 years (scenarios 4-5). We performed comprehensive sensitivity analyses, including on the protection against carriage and serotype replacement. Results: The calibrated model projected for scenario 1 an annual mean of 243 (95%-uncertainty interval: 220-258) expected IMD cases over a 10-year period. Introducing the MenC booster prevented an estimated 5 (3.9-6.7) and the MenACWY booster 8 (6.7-9.1) IMD cases per year on average (scenario 2 and 3). The number-needed-to-vaccinate (NNVs) to prevent one IMD case were 140,000 (100,000-180,000) and 91,000 (76,000-100,000), respectively. To prevent one sequela or death, NNVs were higher (i.e., less efficient). Results were broadly similar for scenarios 4-5. Simulations suggested relevant serotype replacement starting eight-to-ten years after introducing the MenACWY booster. Conclusions: Introducing adolescent MenC or MenACWY boosters marginally reduces the expected IMD burden in Germany. Effectiveness and efficiency of evaluated strategies depend on future incidence. The magnitude of future serotype replacement for the MenACWY vaccine is highly uncertain. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement The work was supported by the Federal Joint Committee (Gemeinsamer Bundesausschuss, G-BA), the highest decision-making body of the joint self-government of physicians, dentists, hospitals and health insurance funds in Germany through the AMSeC project [grant number 01VSF18017]. The views expressed are exclusively those of the authors. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Programming code of the model will be made available upon final publication of the manuscript. Meningococcal IMD case numbers are available from Survstat@RKI (https://survstat.rki.de/).