Effectiveness and efficiency of the meningococcal C toddler vaccination and of introducing meningococcal ACWY toddler and adolescent vaccination in Germany

Background In Germany, primary vaccination against invasive meningococcal disease (IMD) in young children is recommended against serotype C (MenC) since 2005 and B (MenB) since 2024. Because of changes in the epidemiology of serogroups C and Y, we re-evaluated the MenC toddler vaccination, also considering scenarios of MenACWY vaccination.

We used a dynamic-transmission model of meningococcal carriage calibrated to national surveillance data for 10-year simulations. We compared MenC vaccination in toddlers aged 12-23 month with scenarios of (i) no MenC/MenACWY vaccination, (ii) MenACWY toddler vaccination, (iii) MenACWY primary adolescent vaccination, and (iv) combined MenACWY toddler plus adolescent booster vaccination. We compared prevented IMD cases, sequelae and deaths. In sensitivity analyses we varied key assumptions like adolescent vaccine uptake.

The expected annual mean of 243 (95%-uncertainty interval: 220-258) IMD cases with the MenC toddler vaccination increased by 2.9 (2.2-3.7) cases without MenC vaccination, including 1.2 (0.9-1.5) sequelae and 0.2 (0.2-0.3) deaths. Conversely, IMD cases were reduced by 2.4 (1.7-2.9), 1.7 (0.9-2.6), or 6.8 (5.7-7.6), with MenACWY toddler, primary adolescent, or combined toddler and adolescent vaccination, respectively. Preventing one IMD case required 210,000 (170,000-280,000) MenC or 120,000 (98,000-140,000) MenACWY toddler, 99,000 (84,000-110,000) MenACWY toddler and adolescent, and 72,000 (61,000-86,000) MenACWY primary adolescent vaccinations. Effectiveness of adolescent vaccination increased near-linearly with uptake.

Continuing toddler vaccination with MenACWY (or MenC) keeps the IMD burden slightly lower than without toddler vaccination. Yet, introducing MenACWY primary adolescent vaccination was the most efficient scenario, pending sufficient uptake. Serotype carriage requires up-to-date monitoring. Competing Interest Statement The authors have declared no competing interest. Funding Statement The initial development of the model used in this study was supported in part 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 Data availability Code and data for reproducing the results of the modelling study will be made available in a public repository upon final publication of the manuscript. Meningococcal IMD case numbers are available from Survstat@RKI (https://survstat.rki.de/).