Safety and immunogenicity of meningococcus serogroup C conjugate vaccine administered as a primary or booster vaccination to healthy four-year-old children.
BACKGROUND
Meningococcal C conjugate (Men C) vaccines have been routinely used in the UK since November, 1999. Little information exists regarding antibody persistence or immunologic memory after infant vaccination or response to a first dose at 4 years.


METHODS
Ninety-five children immunized at 2, 3 and 4 months of age with 0 or 3 doses of Men C vaccine, boosted with Men C or meningococcal A/C polysaccharide vaccine at 12 months, received a single dose of Men C vaccine at 4 years; 103 age-matched controls were recruited. Pre- and postvaccination Men C IgG (enzyme-linked immunosorbent assay) antibody titers and serum bactericidal activity (SBA) were measured. Safety data were also collected.


RESULTS
Baseline SBA titers of > or =1/4 were observed in 87% of children after at least 3 doses of Men C vaccine in infancy compared with 21% of controls. Reciprocals of postvaccination SBA geometric mean titers in those with four prior doses [3803 (95% confidence interval 3489, 4146)] were significantly higher than controls [33 (95% confidence interval 20, 55)] ( < 0.001). Memory was attenuated by the 12-month meningococcal A/C polysaccharide booster [734 (95% confidence interval 484, 1115)] ( < 0.001). All children had IgG responses to a first dose of Men C vaccine, 80% achieving SBA titers of > or =1/4 (77% > or =1/8). The vaccine was safe and well-tolerated.


CONCLUSIONS
Infant immunization with Men C produced persistent antibody and immunologic memory at 4 years. All children made IgG antibodies after a first dose at this age, with 80% showing bactericidal activity. Clarification of the best measures of Men C vaccine-induced protection is needed, through correlation of immunogenicity data such as this with UK vaccine efficacy estimates.
McVernon
Jodie
J
Oxford Vaccine Group, Department of Pediatrics, John Radcliffe Hospital, Oxford, UK. jodie.mcvernon@paeditrics.ok.ac.uk
Maclennan
Jenny
J
Buttery
Jim
J
Oster
Philipp
P
Danzig
Lisa
L
Moxon
E Richard
ER
D000907:Antibodies, Bacterial / Q000097:blood; D001770:Blood Bactericidal Activity; D002675:Child, Preschool; D005260:Female; D006262:Health; D006801:Humans; D007114:Immunization; D007117:Immunization, Secondary; D007074:Immunoglobulin G / Q000097:blood; D007156:Immunologic Memory; D007223:Infant; D008297:Male; D008589:Meningococcal Infections / Q000276:immunology / Q000517:prevention & control; D022401:Meningococcal Vaccines / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology*; D009345:Neisseria meningitidis / Q000276:immunology
D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D022401:Meningococcal Vaccines; C410218:serogroup C meningococcal conjugate vaccine