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. Methods 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. Results 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. Conclusions 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.