Is a single infant priming dose of meningococcal serogroup C conjugate vaccine in the United Kingdom sufficient?

In 1999, the UK introduced meningococcal serogroup C conjugate (MCC) vaccination at 2, 3, 4 months of age with a single dose for children 1-18 y In 2006, the schedule was refined to a 2 dose priming schedule with a booster in the second year of life. In 2013, the number of priming doses was reduced to a single priming dose, the booster maintained at 12 months of age and an adolescent booster dose introduced. The paper presents the evidence supporting the reduction in the number of priming doses. A UK study provided evidence for reducing the priming doses of MCC-TT together with the positive correlation of lower quantity of antigen and serum bactericidal antibody (SBA) levels post-primary but a higher magnitude of the booster response. Another UK study, demonstrated one dose of MCC-TT or MCC-CRM197 at 3 months gave comparable responses to 2 doses (SBA titres ≥8) both post-primary vaccination and post-booster Hib/MCC-TT at 12 months. However, the magnitude of the SBA GMT was higher in the MCC-TT primed post-booster. A single priming dose of MCC-TT (at 4 or 6 months) compared to 2 doses (2 and 4 months) gave higher SBA titres in all groups, post-primary and post-booster at 12-13 months, with the highest SBA responses observed in the 4 month single dose group. A study in Malta, comparing one dose of MCC-TT or MCC-CRM197 at (3 months) versus 2 doses of MCC-CRM197 (3 and 4 months), showed a high proportion (>84.72%) of subjects achieving SBA titres ≥8 following a single dose. These studies show that a single-dose priming MCC vaccination in infancy is sufficient.