title: Protective Effect of Contemporary Pertussis Vaccines: A Systematic Review and Meta-analysis.
abstract: BACKGROUND
  Acellular pertussis (aP) and whole-cell (wP) pertussis vaccines are presumed to have similar short-term (<3 years after completion of the primary series) efficacy. However, vaccine effect varies between individual pertussis vaccine formulations, and many originally studied formulations are now unavailable. An updated analysis of the short-term protective effect of pertussis vaccines limited to formulations currently on the market in developed countries is needed.
  
  
  METHODS
  We conducted a systematic review and meta-analysis of published studies that evaluated pertussis vaccine efficacy or effectiveness within 3 years after completion (>3 doses) of a primary series of a currently available aP or wP vaccine formulation. The primary outcome was based on the World Health Organization (WHO) clinical case definitions for pertussis. Study quality was assessed using the approach developed by the Child Health Epidemiology Research Group. We determined overall effect sizes using random-effects meta-analyses, stratified by vaccine (aP or wP) and study (efficacy or effectiveness) type.
  
  
  RESULTS
  Meta-analysis of 2 aP vaccine efficacy studies (assessing the 3-component GlaxoSmithKline and 5-component Sanofi-Pasteur formulations) yielded an overall aP vaccine efficacy of 84% (95% confidence interval [CI], 81%-87%). Meta-analysis of 3 wP vaccine effectiveness studies (assessing the Behringwerke, Pasteur/Mérieux, and SmithKline Beecham formulations) yielded an overall wP vaccine effectiveness of 94% (95% CI, 88%-97%) (bothI(2)= 0%).
  
  
  CONCLUSIONS
  Although all contemporary aP and wP formulations protect against pertussis disease, in this meta-analysis the point estimate for short-term protective effect against WHO-defined pertussis in young children was lower for currently available aP vaccines than wP vaccines.
authors.affiliation: Department of Global Health.|Department of Epidemiology, Rollins School of Public Health, Emory University.
authors.forename: T Roice
authors.initials: TR
authors.lastname: Fulton
authors.affiliation: Division of Infectious Diseases, Emory University School of Medicine.
authors.forename: Varun K
authors.initials: VK
authors.lastname: Phadke
authors.affiliation: Emory Vaccine Center.|Department of Pediatrics, Emory University School of Medicine, Atlanta.
authors.forename: Walter A
authors.initials: WA
authors.lastname: Orenstein
authors.affiliation: The Task Force for Global Health, Decatur, Georgia.
authors.forename: Alan R
authors.initials: AR
authors.lastname: Hinman
authors.affiliation: Department of Epidemiology, Rollins School of Public Health, Emory University.
authors.forename: Wayne D
authors.initials: WD
authors.lastname: Johnson
authors.affiliation: Department of Global Health.|Department of Epidemiology, Rollins School of Public Health, Emory University.|Emory Vaccine Center.|Department of Pediatrics, Emory University School of Medicine, Atlanta.
authors.forename: Saad B
authors.initials: SB
authors.lastname: Omer
mesh_terms: D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D010567:Pertussis Vaccine; D016896:Treatment Outcome; D014917:Whooping Cough / Q000276:immunology / Q000517:prevention & control*
chemical_list: D010567:Pertussis Vaccine
keywords: acellular; meta-analysis; pertussis; vaccine efficacy/effectiveness; whole-cell