A novel combined Hib-MenC-TT glycoconjugate vaccine as a booster dose for toddlers : a phase 3 open randomised controlled trial

Abstract

Objective: To study the immunogenicity and reactogenicity of a combined Haemophilus influenzae type b and Neisseria meningitidis serogroup C tetanus toxoid conjugate vaccine (Hib-MenC-TT) when administered as a booster dose in combination with a measles, mumps and rubella vaccine (MMR).

Design: A phase 3 open randomised controlled trial.

Setting: One centre in Oxford, UK and nine centres in Poland.

Subjects: 12–15-month-old healthy children.

Interventions: In the primary stage of the study 500 healthy 6–12-week-old infants were randomised in a 3:1 ratio to receive Hib-MenC-TT+DTPa-IPV or MenC-CRM197 vaccine+DTPa-IPV-Hib. In the booster stage, 476 participants (190 in the UK and 286 in Poland) were vaccinated with Hib-MenC-TT and MMR.

Main outcome measures: The proportion of children with protective serum antibody levels against MenC and Hib 6 weeks following a Hib-MenC-TT booster dose.

Results: The co-primary objectives were met: the Hib-MenC-TT booster dose induced protective antibody titres in children vaccinated with Hib-MenC-TT+DTPa-IPV or MenC-CRM197+DTPa-IPV-Hib at 2, 3 and 4 months of age. 94.8% (lower limit of (LL) 95% CI 92.4) of participants had rSBA-MenC ⩾1:128 and 100% (LL 95% CI 99.2) achieved anti-PRP concentrations ⩾1.0 μg/ml. The percentage of toddlers with a post boost rSBA-MenC of 1:128 was significantly higher after priming with Hib-MenC-TT (97.7%) than after MenC-CRM197 (86%) (difference: 11.7%; 95% CI 6.2 to 19.4).

Conclusion: The waning antibody titres against Hib and MenC following primary immunisation can be boosted to protective levels by administering the Hib-MenC-TT vaccine at 12–15 months of age, supporting the recent introduction of this vaccine in the UK immunisation schedule to sustain protection of children against Hib and MenC disease.