title: The vaccination coverage required to establish herd immunity against influenza viruses.
abstract: OBJECTIVE
  1) To determine the influenza vaccination coverage required to establish herd immunity, and 2) to assess whether the percentages of vaccination coverage proposed and those registered in the United States and Europe are sufficient to establish herd immunity.
  
  
  METHODS
  The vaccination coverage required to establish herd immunity was determined by taking into account the number of secondary cases per infected case (R(o)) and the vaccine effectiveness.
  
  
  RESULTS
  The required percentage that would have been required to establish herd immunity against previous influenza viruses ranged from 13% to 100% for the 1918-19, 1957-58, 1968-69 and 2009-10 pandemic viruses, and from 30% to 40% for the 2008-09 epidemic virus. The objectives of vaccination coverage proposed in the United States - 80% in healthy persons and 90% in high-risk persons - are sufficient to establish herd immunity, while those proposed in Europe - only 75% in elderly and high-risk persons - are not sufficient. The percentages of vaccination coverage registered in the United States and Europe are not sufficient to establish herd immunity.
  
  
  CONCLUSIONS
  The influenza vaccination coverage must be increased in the United States and Europe in order to establish herd immunity. It is necessary to develop new influenza prevention messages based on herd immunity.
authors.affiliation: Public Health Agency, Health Department of Catalonia, Roc Boronat 83-85, Barcelona 08005, Spain. pedro.plans@gencat.cat
authors.forename: Pedro
authors.initials: P
authors.lastname: Plans-Rubió
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks / Q000517:prevention & control* / Q000706:statistics & numerical data; D005060:Europe; D005260:Female; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology / Q000302:isolation & purification; D007252:Influenza Vaccines / Q000627:therapeutic use*; D007251:Influenza, Human / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D058873:Pandemics / Q000517:prevention & control / Q000706:statistics & numerical data; D012307:Risk Factors; D018571:Sentinel Surveillance; D014481:United States; D014611:Vaccination / Q000706:statistics & numerical data* / Q000639:trends
chemical_list: D007252:Influenza Vaccines