Three-year antibody persistence and safety after a single dose of combined haemophilus influenzae type b (Hib)-Neisseria meningitidis Serogroup C-tetanus toxoid conjugate vaccine in hib-primed toddlers

BACKGROUND: Persistence of seroprotective bactericidal antibody titers is important for long-term protection against meningococcal serogroup C disease in young children. Antibody persistence values were determined in children up to 3 years after vaccination with a single dose of the combined Haemophilus influenzae type b (Hib)–Neisseria meningitidis serogroup C (MenC)-tetanus toxoid (TT) conjugate vaccine (Hib-MenC-TT; www.ClinicalTrials.gov: NCT00326118). METHODS: The children had been randomized at ages 12–18 months to receive either 1 dose of Hib-MenC-TT (Hib-MenC group) or separately administered Hib-TT conjugate vaccine and MenC-CRM197 (MCC) vaccine (Hib plus MCC group). All children had been primed in infancy with a Hib vaccine. Antibodies against MenC were measured by a serum bactericidal assay using rabbit complement (rSBA-MenC) and antibodies against Hib polyribosylribitol phosphate were assessed by enzyme-linked immunosorbent assay. RESULTS: The rSBA-MenC titers >=1:8 were demonstrated 3 years after vaccination in 64.2% and 53.2% of participants in the Hib-MenC group and in the Hib plus MCC group, respectively. Antipolyribosylribitol phosphate concentrations >=0.15 µg/mL persisted in >98% of participants in both groups. The rSBA–MenC geometric mean titers and antipolyribosylribitol phosphate geometric mean concentrations remained higher 3 years after vaccination than before vaccination. No serious adverse events assessed by the investigator as being related to vaccination were reported. CONCLUSION: In this antibody persistence study of Hib-primed but MenC-naïve toddlers who received a single dose of Hib-MenC-TT, protective antibody levels against Hib and MenC were maintained in the majority of children 3 years after vaccination.Robert Booy, Peter Richmond, Terry Nolan, Jodie McVernon, Helen Marshall, Michael Nissen, Graham Reynolds, John B. Ziegler, Tanya Stoney, Leon Heron, Stephen Lambert, Narcisa Mesaros, Kavitha Peddiraju, and Jacqueline M. Mille