Immunogenicity of, and immunologic memory to, a reduced primary schedule of meningococcal C-tetanus toxoid conjugate vaccine in infants in the United kingdom.
It has been previously shown that one of the three meningococcal C conjugate (MCC) vaccines introduced in the United Kingdom proved highly immunogenic after the first dose of a three-dose schedule, with evidence of immune memory after dose 3. Thus, in infants a one- or two-dose schedule of this MCC vaccine, conjugated to tetanus toxoid (TT), may suffice. Healthy infants (n = 586) were randomized to receive either one (group 1), two (group 2), or three (group 3) doses of MCC-TT vaccine with a 10- micro g polysaccharide booster given at 13 to 14 months of age. Serum bactericidal antibody (SBA) levels were measured by utilizing rabbit complement (rSBA), meningococcal C-specific immunoglobulin G (IgG), and avidity indices (AIs). For groups 1, 2, and 3, the percentages of infants with an rSBA level of > or =8 against strain C11 were 98.4, 100, and 99.4%, respectively. Infants in group 1 with prevaccination rSBA titers of > or =8 had post-primary MCC rSBA geometric mean titers (GMTs) significantly lower than those infants with prevaccination rSBA titers of <8. One dose of MCC-TT vaccine given to infants at 2 months of age yielded significantly lower SBA GMTs and geometric mean AIs (GMAIs) than two or three doses but elicited a significantly greater response after boosting, as reflected by rSBA levels and GMAI. This study provides the first evidence that the number of doses of MCC-TT used in infant immunization schedules could be decreased.
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000915:Antibody Affinity; D001770:Blood Bactericidal Activity; D005260:Female; D006801:Humans; D007115:Immunization Schedule; D007117:Immunization, Secondary; D007074:Immunoglobulin G / Q000097:blood; D007156:Immunologic Memory; D066298:In Vitro Techniques; D007223:Infant; D008297:Male; D022401:Meningococcal Vaccines / Q000008:administration & dosage* / Q000276:immunology; D009345:Neisseria meningitidis / Q000276:immunology; D011817:Rabbits; D013745:Tetanus Toxoid / Q000008:administration & dosage* / Q000276:immunology; D006113:United Kingdom
D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D022401:Meningococcal Vaccines; D013745:Tetanus Toxoid; C410218:serogroup C meningococcal conjugate vaccine