Immunity against Neisseria meningitidis serogroup C in the Dutch population before and after introduction of the meningococcal c conjugate vaccine.
BACKGROUND
In 2002 a Meningococcal serogroup C (MenC) conjugate vaccine, with tetanus toxoid as carrier protein, was introduced in the Netherlands as a single-dose at 14 months of age. A catch-up campaign was performed targeting all individuals aged 14 months to 18 years. We determined the MenC-specific immunity before and after introduction of the MenC conjugate (MenCC) vaccine.


RESULTS
Two cross-sectional population-based serum banks, collected in 1995/1996 (n = 8539) and in 2006/2007 (n = 6386), were used for this study. The main outcome measurements were the levels of MenC polysaccharide(PS)-specific IgG and serum bactericidal antibodies (SBA) after routine immunization, 4-5 years after catch-up immunization or by natural immunity. There was an increasing persistence of PS-specific IgG and SBA with age in the catch-up immunized cohorts 4-5 years after their MenCC immunization (MenC PS-specific IgG, 0.25 microg/ml (95%CI: 0.19-0.31 microg/ml) at age 6 years, gradually increasing to 2.34 microg/ml,(95%CI: 1.70-3.32 microg/ml) at age 21-22 years). A comparable pattern was found for antibodies against the carrier protein in children immunized above 9 years of age. In case of vaccination before the age of 5 years, PS-specific IgG was rapidly lost. For all age-cohorts together, SBA seroprevalence (> or =8) increased from 19.7% to 43.0% in the pre- and post-MenC introduction eras, respectively. In non-immunized adults the SBA seroprevalence was not significantly different between the pre- and post-MenC introduction periods, whereas PS-specific IgG was significantly lower in the post-MenC vaccination (GMT, age > or =25 years, 0.10 microg/ml) era compared to the pre-vaccination (GMT, age > or =25 years, 0.43 microg/ml) era.


CONCLUSIONS
MenCC vaccination administered above 5 years of age induced high IgG levels compared to natural exposure, increasing with age. In children below 14 months of age and non-immunized cohorts lower IgG levels were observed compared to the pre-vaccination era, whereas functional levels remained similar in adults. Whether the lower IgG poses individuals at increased risk for MenC disease should be carefully monitored. Large-scale introduction of a MenCC vaccine has led to improved protection in adolescents, but in infants a single-dose schedule may not provide sufficient protection on the long-term and therefore a booster-dose early in adolescence should be considered.
de Voer
Richarda M
RM
Laboratory for Infectious Diseases and Screening, National Institute of Public Health and the Environment, Bilthoven, The Netherlands.
Mollema
Liesbeth
L
Schepp
Rutger M
RM
de Greeff
Sabine C
SC
van Gageldonk
Pieter G M
PG
de Melker
Hester E
HE
Sanders
Elisabeth A M
EA
Berbers
Guy A M
GA
van der Klis
Fiona R M
FR
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000918:Antibody Specificity; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007109:Immunity; D017589:Immunization Programs; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D022401:Meningococcal Vaccines / Q000276:immunology*; D008875:Middle Aged; D038542:Neisseria meningitidis, Serogroup C / Q000276:immunology*; D009426:Netherlands; D011134:Polysaccharides / Q000276:immunology; D016036:Seroepidemiologic Studies; D013745:Tetanus Toxoid / Q000276:immunology; D055815:Young Adult
D022401:Meningococcal Vaccines; D011134:Polysaccharides; D013745:Tetanus Toxoid; C410218:serogroup C meningococcal conjugate vaccine