Influence of Prior Meningococcal C Polysaccharide Vaccination on the Response and Generation of Memory after Meningococcal C Conjugate Vaccination in Young Children

This is the authors' abstract. We don't add key points for this paper.

To determine whether the immunological hyporesponsiveness induced by meningococcal AC polysaccharide (MACP) vaccines can be overcome by meningococcal C conjugate (MCC) vaccine in young children, serum bactericidal antibody (SBA) serogroup C-specific IgG and IgG avidity indices were measured in young children who received MACP vaccine, followed 7 months later by MCC vaccine, and their responses were compared with those in age-matched MACP-naive control children, who received a single dose of MCC vaccine. For children <1 year of age at MACP vaccination, the SBA geometric mean titer (GMT) after MCC vaccination was lower (P=.022) and proportions with SBA titers <8 (P=.0083) or <128 (P=.0091) were higher than those in the control children. For older children, there was no difference in the SBA GMTs between the study and control groups (P>.5) or in the proportion with SBA titers <8 (P=1.00) or <128 (P=.98). No increase in avidity occurred after MACP vaccination, whereas avidity increased significantly 1 month after MCC vaccination, with a further increase at 6 months, which indicates that the induction of immunological memory was not impaired.