title: Acellular pertussis vaccine at birth and one month induces antibody responses by two months of age.
abstract: BACKGROUND
  Infants less than 3 months of age are at highest risk of hospitalization and death from pertussis. Several studies have examined antibody responses to pertussis vaccines at birth but no previous study has evaluated 2 doses of monovalent acellular pertussis vaccine (aPV) before 2 months of age.
  
  
  METHODS
  Seventy-six newborns were randomized at birth to 3 groups-aPV at birth and 1 month, aPV at birth, and control. All infants received hepatitis B vaccine (HBV) at birth followed at 2, 4, and 6 months by a combination vaccine including aPV, diphtheria, tetanus, Haemophilus influenzae type b (Hib), hepatitis B, polio antigens and 7 valent conjugate pneumococcal vaccine. IgG antibody responses to pertussis toxoid (PT), filamentous hemagglutinin (FHA), and pertactin (PRN) were measured in maternal serum and in infants at 2, 4, 6, and 8 months of age. Antibody responses to hepatitis B, diphtheria, tetanus, and Hib were measured at 8 months only. A parental diary and active telephone follow-up occurred for 7 days after each vaccination.
  
  
  RESULTS
  The aPV birth dose was well tolerated. By 2 months of age, 22 of 25 (88%) of 2 dose recipients had detectable IgG antibody to PT (IgG PT) compared with 9 of 21 (43%) who received a birth dose only and 3 of 20 (15%) of controls. Infants in the 2 dose group had a geometric mean concentration (GMC) of IgG PT of 16 ELISA units per mL (EU/mL), 95% CI: 11 to 25, significantly higher than birth dose only (5 EU/mL, 95% CI: 3-8) and controls (3 EU/mL, 95% CI: 2-5). At 8 months of age, following 5, 4, and 3 doses of aP-containing vaccine, respectively, IgG PT had plateaued but IgG to FHA and PRN increased with successive doses. There was a trend to lower antibody responses for hepatitis B and Hib with higher numbers of Pa doses.
  
  
  CONCLUSIONS
  These data suggest that aPV at birth and 1 month induces significantly higher IgG antibody against pertussis antigens by 2 months of age without reducing subsequent pertussis antibody responses. Larger and more detailed studies of aPV from birth are needed to evaluate other antibody responses and the potential of this approach to reduce death and morbidity from Bordetella pertussis infection in the first 3 months of life.
authors.affiliation: National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases, The Children's Hospital at Westmead and the University of Sydney, New South Wales, Australia. nicholw3@chw.edu.au
authors.forename: Nicholas
authors.initials: N
authors.lastname: Wood
authors.forename: Peter
authors.initials: P
authors.lastname: McIntyre
authors.forename: Helen
authors.initials: H
authors.lastname: Marshall
authors.forename: Don
authors.initials: D
authors.lastname: Roberton
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood*; D000914:Antibodies, Viral / Q000097:blood; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000008:administration & dosage / Q000276:immunology; D005260:Female; D018073:Haemophilus Vaccines / Q000008:administration & dosage / Q000276:immunology; D017325:Hepatitis B Vaccines / Q000008:administration & dosage / Q000276:immunology; D006801:Humans; D007117:Immunization, Secondary / Q000379:methods*; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010567:Pertussis Vaccine / Q000008:administration & dosage* / Q000276:immunology*; D011054:Poliovirus Vaccine, Inactivated / Q000008:administration & dosage / Q000276:immunology; D014611:Vaccination / Q000379:methods*; D022282:Vaccines, Acellular / Q000008:administration & dosage / Q000276:immunology; D017778:Vaccines, Combined; D018074:Vaccines, Conjugate / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D000914:Antibodies, Viral; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D018073:Haemophilus Vaccines; D017325:Hepatitis B Vaccines; D010567:Pertussis Vaccine; D011054:Poliovirus Vaccine, Inactivated; D022282:Vaccines, Acellular; D017778:Vaccines, Combined; D018074:Vaccines, Conjugate; C541235:diphtheria-tetanus-acellular pertussis-inactivated poliovirus-Haemophilus influenzae b conjugate-hepatitis B vaccine