title: Assessment of immunogenicity and safety following primary and booster immunisation with a CRM197 -conjugated Haemophilus influenzae type B vaccine in healthy Chinese infants.
abstract: BACKGROUND
  Invasive meningitis and pneumonia caused by Haemophilus influenzae type b (Hib) is an important cause of childhood mortality in countries where Hib vaccination is not routine. We evaluated the non-inferiority of a licensed Hib vaccine, PRP-CRM(197) compared with a second licensed Hib vaccine, PRP-T, following the recommended Chinese immunisation schedule for infants between 6 months and 1 year of age.
  
  
  METHODS
  In the first study phase, 6-12 month-old infants received two primary doses of either PRP-CRM(197) (n = 335) or PRP-T (n = 335) vaccine administered 1 month apart. In the second study phase 8 months later, the same children received a single booster dose of vaccine identical to that use for priming (PRP-CRM(197), n = 327; PRP-T, n = 333). Serum levels of anti-polyribosylribitol phosphate (PRP) antibodies were measured using enzyme-linked immunosorbent assay (ELISA). Non-inferiority of primary and booster doses was assessed in terms of percentages of subjects with anti-PRP antibody levels associated with providing short-term (≥ 0.15 μg/ml) and long-term (≥ 1.0 μg/ml) protection; the non-inferiority margin was set at -5%.
  
  
  RESULTS
  PRP-CRM(197) was demonstrated to be non-inferior to PRP-T. Anti-PRP antibodies levels ≥ 0.15 μg/ml and ≥ 1.0 μg/ml were achieved by 97% of infants in the PRP-CRM(197) group and 98% of infants in the PRP-T group 1 month after primary immunisation, and by all subjects (100%) in both vaccine groups 1 month after booster administration. Safety profiles for both vaccines were similar; no serious adverse events, deaths or adverse events leading to withdrawal occurred during the study.
  
  
  CONCLUSIONS
  PRP-CRM(197) was well-tolerated and immunologically non-inferior to a licensed comparator Hib vaccine in Chinese infants (Clinicaltrials.gov: NCT01044316 & NCT01226953).
authors: Hebei Centre for Disease Control and Prevention, Shijiazhuang, China.
authors: L
authors: L
authors: Jun
authors: C
authors: C
authors: Yuguo
authors: W
authors: W
authors: Zhiguo
authors: L
authors: L
authors: Jinfeng
authors: M
authors: M
authors: Huawei
authors: L
authors: L
authors: Xiuhua
authors: Z
authors: Z
authors: Yonggui
authors: X
authors: X
authors: Yanhua
authors: Y
authors: Y
authors: Kong
authors: L
authors: L
authors: Hongtao
authors: Z
authors: Z
authors: Yuliang
mesh_terms: D000917:Antibody Formation / Q000276:immunology; D001426:Bacterial Proteins / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006192:Haemophilus Infections / Q000276:immunology / Q000517:prevention & control*; D019741:Haemophilus influenzae type b / Q000276:immunology*; D006801:Humans; D007117:Immunization, Secondary / Q000379:methods; D007223:Infant; D008297:Male; D016896:Treatment Outcome
chemical_list: D001426:Bacterial Proteins; C028581:CRM197 (non-toxic variant of diphtheria toxin)