title: Influenza vaccination in young children reduces influenza-associated hospitalizations in older adults, 2002-2006.
abstract: OBJECTIVE
  To assess how influenza vaccination coverage in children is related to pneumonia and influenza (P&I) in older adults and whether sociodemographic factors modify these associations.
  
  
  METHODS
  Approximately 5 million hospitalization records from the Centers for Medicare and Medicaid Services for four influenza years (2002-2006) were abstracted. A single-year age distribution of rates of P&I hospitalization was estimated according to state for each influenza season; an exponential acceleration in the P&I rates with age was observed for each influenza season. State- and season-specific P&I rate accelerations were regressed against the percentage of vaccinated children, older adults, or both using mixed effects models.
  
  
  METHODS
  U.S. population, 2002 to 2006.
  
  
  METHODS
  U.S. population aged 65 and older.
  
  
  METHODS
  State-level influenza annual vaccination coverage data in children and older adults were obtained from the National Immunization Survey and the Behavioral Risk Factor Surveillance System, respectively.
  
  
  RESULTS
  Child influenza vaccination coverage was negatively associated with age acceleration in P&I, whereas influenza vaccination in the older adults themselves was not significantly associated with P&I in older adults.
  
  
  CONCLUSIONS
  Vaccination of children against influenza may induce herd immunity against influenza for older adults and has the potential to be more beneficial to older adults than the existing policy of preventing influenza by vaccinating older adults themselves.
authors.affiliation: Initiative for the Forecasting and Modeling of Infectious Disease, Tufts University, Boston, Massachusetts, USA. steven_a.cohen@tufts.edu
authors.forename: Steven A
authors.initials: SA
authors.lastname: Cohen
authors.forename: Kenneth K H
authors.initials: KK
authors.lastname: Chui
authors.forename: Elena N
authors.initials: EN
authors.lastname: Naumova
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D006760:Hospitalization / Q000639:trends*; D006801:Humans; D015994:Incidence; D007252:Influenza Vaccines / Q000008:administration & dosage*; D007251:Influenza, Human / Q000453:epidemiology / Q000517:prevention & control*; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology; D014611:Vaccination / Q000379:methods*
chemical_list: D007252:Influenza Vaccines