A randomized, multicenter, open-label clinical trial to assess the immunogenicity of a meningococcal C vaccine booster dose administered to children aged 14 to 18 months.
BACKGROUND
A booster meningococcal C (MenC) vaccine dose is recommended after the first year of life. The objective of this study was to assess its immunogenicity and factors that modify the immunoresponse.


METHODS
An open label study in which 389 children 14 to 18 months of age, previously primed with 3 doses of a MenC vaccine conjugated with CRM197 (MenC-CRM) or with 2 doses of a MenC vaccine conjugated with tetanus toxoid (MenC-TT), were randomized to be boosted with either of these vaccines and a DTaP-IPV-Hib vaccine at the same time. Immunogenicity against MenC and Haemophilus influenzae type b was assessed before and 1 month after the booster dose.


RESULTS
Before the second year booster, 44.9% of the studied children had MenC bactericidal (SBA) seroprotection rate of > or =1:8, with no differences related to the vaccine used for priming, whereas the anti Hib antibody concentration was higher in children primed with the MenC-TT (0.59; 95% CI: 0.49-0.71 vs. 0.39; 95% CI: 0.32-0.48).One month after the MenC vaccine booster 99.5% of the children had SBA > or =1:128. Children primed with MenC-TT reached higher SBA titers: 6520 (95% CI: 5359-7932) than those primed with MenC-CRM: 1903 (95% CI: 1600-2262). Children primed with MenC-CRM had SBA titers of 2061 (95% CI: 1599-2627) when boosted with MenC-TT and 1746 (95% CI: 1378-2213) when boosted with MenC-CRM. Children primed with MenC-TT had SBA titers of 6786 (95% CI: 5023-9167) and 6278 (95% CI: 4841-8144) when boosted with MenC-TT or MenC-CRM. There was no difference in the PRP antibody concentration after boosting.


CONCLUSIONS
A booster MenC dose induces high SBA and anti Hib response with over 99% of children seroprotected. Children primed with a MenC-TT vaccine reached SBA titers 3.5 times higher no matter which vaccine was used for boosting.
Díez-Domingo
Javier
J
CSISP, Centro Superior de Investigación en Salud Pública (Center for public health research), Valencia, Spain. diez_jav@gva.es
Cantarino
M Victoria Planelles
MV
Torrentí
Jose M Baldó
JM
Sansano
M Isabel Ubeda
MI
Rosich
Angels Jubert
AJ
Merino
Angel Hernández
AH
de Miguel
Angel Gil
AG
González
Javier Blanco
JB
Marcos
Mar Duelo
MD
D000907:Antibodies, Bacterial / Q000276:immunology; D001426:Bacterial Proteins / Q000276:immunology; D001770:Blood Bactericidal Activity; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000276:immunology; D018073:Haemophilus Vaccines / Q000276:immunology; D006801:Humans; D007117:Immunization, Secondary / Q000379:methods*; D007223:Infant; D008297:Male; D008589:Meningococcal Infections / Q000517:prevention & control*; D022401:Meningococcal Vaccines / Q000235:genetics / Q000276:immunology*; D038542:Neisseria meningitidis, Serogroup C / Q000276:immunology*; D011054:Poliovirus Vaccine, Inactivated / Q000276:immunology; D013745:Tetanus Toxoid / Q000276:immunology; D018074:Vaccines, Conjugate / Q000276:immunology
D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D018073:Haemophilus Vaccines; D022401:Meningococcal Vaccines; D011054:Poliovirus Vaccine, Inactivated; D013745:Tetanus Toxoid; D018074:Vaccines, Conjugate; C541234:diphtheria-tetanus-five component acellular pertussis-inactivated poliomyelitis -Haemophilus influenzae type b conjugate vaccine; C028581:CRM197 (non-toxic variant of diphtheria toxin)