title: Estimation of influenza-attributable medically attended acute respiratory illness by influenza type/subtype and age, Germany, 2001/02-2014/15.
abstract: The total burden of influenza in primary care is difficult to assess. The case definition of medically attended "acute respiratory infection" (MAARI) in the German physician sentinel is sensitive; however, it requires modelling techniques to derive estimates of disease attributable to influenza. We aimed to examine the impact of type/subtype and age.
  
  
  
  Data on MAARI and virological results of respiratory samples (virological sentinel) were available from 2001/02 until 2014/15. We constructed a generalized additive regression model for the periodic baseline and the secular trend. The weekly number of influenza-positive samples represented influenza activity. In a second step, we distributed the estimated influenza-attributable MAARI (iMAARI) according to the distribution of types/subtypes in the virological sentinel.
  
  
  
  Season-specific iMAARI ranged from 0.7% to 8.9% of the population. Seasons with the strongest impact were dominated by A(H3), and iMAARI attack rate of the pandemic 2009 (A(H1)pdm09) was 4.9%. Regularly the two child age groups (0-4 and 5-14 years old) had the highest iMAARI attack rates reaching frequently levels up to 15%-20%. Influenza B affected the age group of 5- to 14-year-old children substantially more than any other age group. Sensitivity analyses demonstrated both comparability and stability of the model.
  
  
  
  We constructed a model that is well suited to estimate the substantial impact of influenza on the primary care sector. A(H3) causes overall the greatest number of iMAARI, and influenza B has the greatest impact on school-age children. The model may incorporate time series of other pathogens as they become available.
authors.affiliation: Department of Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: An der Heiden
authors.affiliation: Department of Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany.
authors.forename: Udo
authors.initials: U
authors.lastname: Buchholz
mesh_terms: D000208:Acute Disease / Q000453:epidemiology; D000293:Adolescent; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D017281:Cost of Illness; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000302:isolation & purification*; D053122:Influenza A Virus, H3N2 Subtype / Q000235:genetics / Q000302:isolation & purification*; D007251:Influenza, Human / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000821:virology*; D008297:Male; D008962:Models, Theoretical; D058873:Pandemics; D012141:Respiratory Tract Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000821:virology*; D012621:Seasons; D014611:Vaccination
keywords: Germany; burden of disease; generalised additive model; influenza; influenza type/subtype; medically attended acute respiratory illness