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
From the *National Centre for Immunisation Research and Surveillance (NCIRS), The Children’s Hospital at Westmead, Sydney; †School of Paediatrics and Child Health, University of Western Australia and Princess Margaret Hospital for Children, Perth; ‡Murdoch Children’s Research Institute and Melbourne School of Population Health, University of Melbourne, Parkville; §Women’s and Children’s Hospital and University of Adelaide, Adelaide; ¶Royal Children’s Hospital, Brisbane; ‖Canberra Hospital, Woden; **Sydney Children’s Hospital, Randwick; ††Vaccine Trials Group, Telethon Institute for Child Health Research, Perth, Australia; ‡‡GlaxoSmithKline Biologicals, Wavre, Belgium; §§GlaxoSmithKline Biologicals, Bangalore, India; and ¶¶GlaxoSmithKline Biologicals, King of Prussia, PA.
Checking for direct PDF access through Ovid
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.