title: An evidence synthesis approach to estimating the incidence of symptomatic pertussis infection in the Netherlands, 2005-2011.
abstract: BACKGROUND
  Despite high vaccination coverage, infection with Bordetella pertussis is a current public health concern in the Netherlands and other European Union member states. Because surveillance data are subject to extensive under-ascertainment and under-reporting, incidence is difficult to determine. Our objective was to estimate the age-group specific incidence of symptomatic pertussis infection in the Netherlands over the period 2005-2011, using multi-parameter evidence synthesis.
  
  
  METHODS
  Age-specific seroconversion probabilities were estimated for 2007 using Netherlands population data stratified by age-group and cross-sectional population-wide serosurvey (PIENTER-2) data, with a sero-diagnostic cut-off of 125 EU/ml as a proxy for recent infection. Symptomatic probabilities were derived from a study of household contacts and from PIENTER-2. The annual number of symptomatic infected (SI) persons was estimated using evidence synthesis methods in a Bayesian framework, by combining the estimated incidence of infection with notification data and symptomatic probabilities.
  
  
  RESULTS
  An incidence rate of 128 SI cases per 10,000 population (95 % credible interval [CrI]: 110-150) was estimated for 2005, which decreased to 107 per 10,000 (95 % CrI: 91-126) for 2011. The degree of underestimation in statutory notified cases was age-dependent, ranging from 10-fold (10-19 years) to 69-fold (60+ years). The largest annual decreases in SI incidence rate over the study period were in the 1-4 and 5-9 years age-groups (24.3 %, 15.9 % per year, respectively).
  
  
  CONCLUSIONS
  By synthesising all available data, the incidence of symptomatic pertussis and the extent to which SI is underrepresented by notification data can be estimated. Such estimates are essential for disease burden computation and for informing public health priority-setting.
authors.affiliation: Centre for Infectious Disease Control, National Institute for Public Health and the Environment, PO Box 1, 3720 BA, Bilthoven, Netherlands. scott.mcdonald@rivm.nl.
authors.forename: Scott A
authors.initials: SA
authors.lastname: McDonald
authors.affiliation: Centre for Infectious Disease Control, National Institute for Public Health and the Environment, PO Box 1, 3720 BA, Bilthoven, Netherlands. peter.teunis@rivm.nl.
authors.forename: Peter
authors.initials: P
authors.lastname: Teunis
authors.affiliation: Centre for Infectious Disease Control, National Institute for Public Health and the Environment, PO Box 1, 3720 BA, Bilthoven, Netherlands. nicoline.van.der.maas@rivm.nl.
authors.forename: Nicoline
authors.initials: N
authors.lastname: van der Maas
authors.affiliation: Centre for Infectious Disease Control, National Institute for Public Health and the Environment, PO Box 1, 3720 BA, Bilthoven, Netherlands. sabine.de.greeff@rivm.nl.
authors.forename: Sabine
authors.initials: S
authors.lastname: de Greeff
authors.affiliation: Centre for Infectious Disease Control, National Institute for Public Health and the Environment, PO Box 1, 3720 BA, Bilthoven, Netherlands. hester.de.melker@rivm.nl.
authors.forename: Hester
authors.initials: H
authors.lastname: de Melker
authors.affiliation: Centre for Infectious Disease Control, National Institute for Public Health and the Environment, PO Box 1, 3720 BA, Bilthoven, Netherlands. mirjam.kretzschmar@rivm.nl.|Julius Centre for Health Sciences and Primary Care, University Medical Centre Utrecht, PO Box 85500, 3508 GA, Utrecht, Netherlands. mirjam.kretzschmar@rivm.nl.
authors.forename: Mirjam E
authors.initials: ME
authors.lastname: Kretzschmar
mesh_terms: D000293:Adolescent; D000328:Adult; D001499:Bayes Theorem; D001886:Bordetella pertussis / Q000472:pathogenicity; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007223:Infant; D008875:Middle Aged; D008962:Models, Theoretical; D009426:Netherlands / Q000453:epidemiology; D010567:Pertussis Vaccine / Q000627:therapeutic use; D011634:Public Health; D014611:Vaccination; D014917:Whooping Cough / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D010567:Pertussis Vaccine