title: Combined tetanus-diphtheria and pertussis vaccine during pregnancy: transfer of maternal pertussis antibodies to the newborn.
abstract: OBJECTIVE
  Pertussis is currently an emerging public health concern in some countries with high vaccination coverage. It is expected that maternal pertussis immunization could provide newborn protection. We compared pertussis toxin antibody (anti-PT) levels in women during pregnancy (pre- and post-vaccination) with respect to levels in the newborn at delivery in women vaccinated during pregnancy. We also estimated anti-PT titers at primary infant vaccination.
  
  
  METHODS
  Observational study of pregnant women vaccinated with Tdap (≥20 weeks gestation) and their newborns between May 2012 and August 2013. Anti-PT levels were determined by ELISA in maternal (pre- and post-vaccination) and newborn blood.
  
  
  RESULTS
  Pre-vaccination, post-vaccination maternal and newborn samples were available in 132 subjects. Mean maternal age was 34.2 (SD 4.3) years. Median weeks of gestation at vaccination were 27.2 (Q1-Q3 21.7-30.8). Anti-PT (≥10 IU/ml) levels were found in 37.1% of maternal pre-vaccination samples (geometric mean titer (GMT) 7.9 IU/ml (95% CI 6.8-9.2)), 90.2% of post-vaccination samples (GMT 31.1 IU/ml (95% CI 26.6-36.3)) and 94.7% of newborns (GMT 37.8 IU/ml (95% CI 32.3-44.1)). The Lin concordance index between post-vaccination maternal and newborn samples was 0.8 (95% CI 0.8-0.9). Transplacental transfer ratio was 146.6%. At two months of age, 66% of newborns had estimated anti-PT levels ≥10 IU/ml.
  
  
  CONCLUSIONS
  There was a high correlation between anti-PT levels in mothers and newborns, with higher levels in newborns, which should be sufficient to provide protection against pertussis during the first months of life. Vaccination of pregnant women seems to be an immunogenic strategy to protect newborns until primary infant immunization.
authors.affiliation: Department of Preventive Medicine and Epidemiology, Hospital Clínic de Barcelona, Universitat de Barcelona, Barcelona, Spain; ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.
authors.forename: Alba
authors.initials: A
authors.lastname: Vilajeliu
authors.affiliation: Department of Maternal-Fetal Medicine, BCNatal-Barcelona Center of Maternal-Fetal and Neonatal Medicine, Hospital Clínic and Hospital Sant Joan de Déu, IDIBAPS, Universitat de Barcelona, and Centre for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain.
authors.forename: Anna
authors.initials: A
authors.lastname: Goncé
authors.affiliation: Department of Maternal-Fetal Medicine, BCNatal-Barcelona Center of Maternal-Fetal and Neonatal Medicine, Hospital Clínic and Hospital Sant Joan de Déu, IDIBAPS, Universitat de Barcelona, and Centre for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: López
authors.affiliation: Department of Microbiology, Hospital Clínic-IDIBAPS, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Josep
authors.initials: J
authors.lastname: Costa
authors.affiliation: Department of Microbiology, Hospital Clínic-IDIBAPS, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Rocamora
authors.affiliation: Biostatistics and Data Management Core Facility, Hospital Clínic-IDIBAPS, Biostatistics Unit, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: José
authors.initials: J
authors.lastname: Ríos
authors.affiliation: Department of Maternal-Fetal Medicine, BCNatal-Barcelona Center of Maternal-Fetal and Neonatal Medicine, Hospital Clínic and Hospital Sant Joan de Déu, IDIBAPS, Universitat de Barcelona, and Centre for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain.
authors.forename: Irene
authors.initials: I
authors.lastname: Teixidó
authors.affiliation: Department of Preventive Medicine and Epidemiology, Hospital Clínic de Barcelona, Universitat de Barcelona, Barcelona, Spain. Electronic address: jmbayas@clinic.ub.es.
authors.forename: José M
authors.initials: JM
authors.lastname: Bayas
mesh_terms: D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology*; D001886:Bordetella pertussis / Q000276:immunology*; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000276:immunology*; D005260:Female; D006801:Humans; D007112:Immunity, Maternally-Acquired; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007231:Infant, Newborn; D008875:Middle Aged; D037342:Pertussis Toxin / Q000276:immunology; D011247:Pregnancy; D013997:Time Factors; D014917:Whooping Cough / Q000276:immunology / Q000517:prevention & control; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D007074:Immunoglobulin G; D037342:Pertussis Toxin
keywords: Antibody transfer; Neonatal pertussis; Pregnancy; Vaccination