title: Meningococcal group C and w135 immunological hyporesponsiveness in african toddlers.
abstract: A phase II clinical study was conducted in African toddlers (aged 12 to 23 months), with subjects receiving either investigational meningococcal group A conjugate (PsA-TT), meningococcal ACWY polysaccharide (PsACWY), or Haemophilus influenzae type b (Hib-TT) vaccine. Ten months following vaccination, the 3 study groups were further randomized to receive a dose of PsA-TT, a 1/5 dose of PsACWY, or a dose of Hib-TT vaccine. Group A serum bactericidal antibody (SBA) results have been reported previously, with PsA-TT demonstrating superior immunogenicity versus PsACWY vaccine. Immunogenicity for serogroups W135 and C was assessed by SBA assay to investigate the impact of multiple doses in this age group. Blood samples were taken prior to vaccination, 28 days and 40 weeks post-primary vaccination, and 7 and 28 days post-booster vaccination with a 1/5 dose of PsACWY. Subjects who had previously received a full dose of PsACWY had W135 SBA geometric mean titers (GMTs) of 26.1 and 4.4 at 7 and 28 days post-booster vaccination with a 1/5 PsACWY dose, respectively, whereas the W135 SBA GMTs of naïve subjects at these time points following vaccination with a 1/5 dose of PsACWY were 861.1 and 14.6, respectively. Similar differences were observed for serogroup C, with SBA GMTs of 99 and 5.9 at 7 and 28 days post-booster vaccination with a 1/5 dose of PsACWY, respectively, for naïve subjects, compared to 4.1 and 3.2 for previously vaccinated subjects. Immunologic hyporesponsiveness for groups C and W135 was observed following a full dose of PsACWY vaccine at 12 to 23 months of age and a 1/5 dose of PsACWY 10 months later compared to the case for PsACWY-naïve subjects receiving a 1/5 dose of PsACWY vaccine.
authors.affiliation: Vaccine Evaluation Unit, Health Protection Agency North West, P.O. Box 209, Clinical Sciences Building, Manchester Royal Infirmary, Manchester M13 9WZ, United Kingdom. helen.findlow@hpa.org.uk
authors.forename: Helen
authors.initials: H
authors.lastname: Findlow
authors.forename: Samba
authors.initials: S
authors.lastname: Sow
authors.forename: Ray
authors.initials: R
authors.lastname: Borrow
authors.forename: Milagritos
authors.initials: M
authors.lastname: Tapia
authors.forename: Fadima Cheick
authors.initials: FC
authors.lastname: Haidara
authors.forename: Adebayo K
authors.initials: AK
authors.lastname: Akinsola
authors.forename: Olubukola T
authors.initials: OT
authors.lastname: Idoko
authors.forename: Fatoumata
authors.initials: F
authors.lastname: Diallo
authors.forename: Richard
authors.initials: R
authors.lastname: Adegbola
authors.forename: Yuxiao
authors.initials: Y
authors.lastname: Tang
authors.forename: Varsha
authors.initials: V
authors.lastname: Parulekar
authors.forename: Helen
authors.initials: H
authors.lastname: Chadha
authors.forename: Lesley
authors.initials: L
authors.lastname: Mabey
authors.forename: Daniel
authors.initials: D
authors.lastname: Holme
authors.forename: Kelly
authors.initials: K
authors.lastname: Townsend
authors.forename: Julie
authors.initials: J
authors.lastname: Chaumont
authors.forename: F Marc
authors.initials: FM
authors.lastname: Laforce
authors.forename: Prasad S
authors.initials: PS
authors.lastname: Kulkarni
authors.forename: Elisa
authors.initials: E
authors.lastname: Marchetti
authors.forename: Simonetta
authors.initials: S
authors.lastname: Viviani
authors.forename: Musa
authors.initials: M
authors.lastname: Hassan-King
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Preziosi
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis / Q000097:blood*; D001770:Blood Bactericidal Activity / Q000276:immunology; D005714:Gambia; D006801:Humans; D017589:Immunization Programs; D007117:Immunization, Secondary; D007223:Infant; D008302:Mali; D008585:Meningitis, Meningococcal / Q000517:prevention & control; D008589:Meningococcal Infections / Q000517:prevention & control; D022401:Meningococcal Vaccines / Q000008:administration & dosage / Q000276:immunology*; D009345:Neisseria meningitidis / Q000145:classification / Q000276:immunology; D038542:Neisseria meningitidis, Serogroup C / Q000276:immunology*; D038582:Neisseria meningitidis, Serogroup W-135 / Q000276:immunology*; D011817:Rabbits; D012703:Serotyping; D016896:Treatment Outcome; D018074:Vaccines, Conjugate / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D022401:Meningococcal Vaccines; D018074:Vaccines, Conjugate