Quadrivalent meningococcal tetanus toxoid-conjugate booster vaccination in children aged 10-12 years: phase III randomized trial complementary analysis of immune persistence 3-6 years after priming.

Immune persistence following primary vaccination with a single dose of meningococcal quadrivalent conjugate vaccines, MenACYW-TT/MCV4-CRM, at age 10-12 years was demonstrated. Most participants primed with MenACYW-TT and MCV4-CRM maintained seroprotective titers against all serogroups, suggesting continued protection. Priming with MenACYW-TT resulted in higher persistent titers for serogroups C, W, and Y than MCV4-CRM. A MenACYW-TT booster induced a robust immune response; almost all participants achieved seroprotection against all serogroups. This analysis supports the ACIP recommendations for routine administration of a primary dose of a meningococcal ACWY conjugate vaccine at 11-12 years, with a booster dose at 16 years.