title: Understanding Trends in Pertussis Incidence: An Agent-Based Model Approach.
abstract: OBJECTIVE
  We examined the impact of undetected infections, adult immunity, and waning vaccine-acquired immunity on recent age-related trends in pertussis incidence.
  
  
  METHODS
  We developed an agent-based model of pertussis transmission in Dakota County, Minnesota using case data from the Minnesota Department of Health. For outbreaks in 2004, 2008, and 2012, we fit our model to incidence in 3 children's age groups relative to adult incidence. We estimated parameters through model calibration.
  
  
  RESULTS
  The duration of vaccine-acquired immunity after completion of the 5-dose vaccination series decreased from 6.6 years in the 2004 model to approximately 3.0 years in the 2008 and 2012 models. Tdap waned after 2.1 years in the 2012 model. A greater percentage of adults were immune in the 2008 model than in the 2004 and 2012 models. On average, only 1 in 10 adult infections was detected, whereas 8 in 10 child infections were detected.
  
  
  CONCLUSIONS
  The observed trends in relative pertussis incidence in Dakota County can be attributed in part to fluctuations in adult immunity and waning vaccine-acquired immunity. No single factor accounts for current pertussis trends.
authors.affiliation: Erinn Sanstead, Seth Rowley, Shalini Kulasingam, and Eva Enns are with the School of Public Health, University of Minnesota, Minneapolis. Erinn Sanstead, Cynthia Kenyon, Seth Rowley, Claudia Miller, and Kristen Ehresmann are with the Division of Infectious Disease Epidemiology, Prevention, and Control, Minnesota Department of Health, St. Paul.
authors.forename: Erinn
authors.initials: E
authors.lastname: Sanstead
authors.affiliation: Erinn Sanstead, Seth Rowley, Shalini Kulasingam, and Eva Enns are with the School of Public Health, University of Minnesota, Minneapolis. Erinn Sanstead, Cynthia Kenyon, Seth Rowley, Claudia Miller, and Kristen Ehresmann are with the Division of Infectious Disease Epidemiology, Prevention, and Control, Minnesota Department of Health, St. Paul.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Kenyon
authors.affiliation: Erinn Sanstead, Seth Rowley, Shalini Kulasingam, and Eva Enns are with the School of Public Health, University of Minnesota, Minneapolis. Erinn Sanstead, Cynthia Kenyon, Seth Rowley, Claudia Miller, and Kristen Ehresmann are with the Division of Infectious Disease Epidemiology, Prevention, and Control, Minnesota Department of Health, St. Paul.
authors.forename: Seth
authors.initials: S
authors.lastname: Rowley
authors.affiliation: Erinn Sanstead, Seth Rowley, Shalini Kulasingam, and Eva Enns are with the School of Public Health, University of Minnesota, Minneapolis. Erinn Sanstead, Cynthia Kenyon, Seth Rowley, Claudia Miller, and Kristen Ehresmann are with the Division of Infectious Disease Epidemiology, Prevention, and Control, Minnesota Department of Health, St. Paul.
authors.forename: Eva
authors.initials: E
authors.lastname: Enns
authors.affiliation: Erinn Sanstead, Seth Rowley, Shalini Kulasingam, and Eva Enns are with the School of Public Health, University of Minnesota, Minneapolis. Erinn Sanstead, Cynthia Kenyon, Seth Rowley, Claudia Miller, and Kristen Ehresmann are with the Division of Infectious Disease Epidemiology, Prevention, and Control, Minnesota Department of Health, St. Paul.
authors.forename: Claudia
authors.initials: C
authors.lastname: Miller
authors.affiliation: Erinn Sanstead, Seth Rowley, Shalini Kulasingam, and Eva Enns are with the School of Public Health, University of Minnesota, Minneapolis. Erinn Sanstead, Cynthia Kenyon, Seth Rowley, Claudia Miller, and Kristen Ehresmann are with the Division of Infectious Disease Epidemiology, Prevention, and Control, Minnesota Department of Health, St. Paul.
authors.forename: Kristen
authors.initials: K
authors.lastname: Ehresmann
authors.affiliation: Erinn Sanstead, Seth Rowley, Shalini Kulasingam, and Eva Enns are with the School of Public Health, University of Minnesota, Minneapolis. Erinn Sanstead, Cynthia Kenyon, Seth Rowley, Claudia Miller, and Kristen Ehresmann are with the Division of Infectious Disease Epidemiology, Prevention, and Control, Minnesota Department of Health, St. Paul.
authors.forename: Shalini
authors.initials: S
authors.lastname: Kulasingam
mesh_terms: D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D022681:Diphtheria-Tetanus-acellular Pertussis Vaccines / Q000008:administration & dosage*; D004196:Disease Outbreaks; D006801:Humans; D015994:Incidence; D007223:Infant; D008910:Minnesota; D014917:Whooping Cough / Q000453:epidemiology* / Q000276:immunology*; D055815:Young Adult
chemical_list: D022681:Diphtheria-Tetanus-acellular Pertussis Vaccines