title: Features of the new pandemic influenza A/H1N1/2009 virus: virology, epidemiology, clinical and public health aspects.
abstract: OBJECTIVE
  The emergence of the pandemic A/H1N1/2009 influenza virus has enabled preexisting pandemic influenza plans to be put into action. This review examines the clinical and public health impact of this new virus.
  
  
  RESULTS
  Although early figures suggested that this pandemic virus was causing higher morbidity and mortality than seasonal influenza viruses, subsequent studies have found it to cause milder disease in most cases. Yet, there are some groups with increased risk of serious disease from this new pathogen. The widespread use of antiviral agents, prophylactically and therapeutically, has led to the sporadic emergence of drug resistance, though this is still rare. Nonpharmacological public health interventions for containment and mitigation have been relatively ineffective in limiting the rapid, global spread of this pathogen. Recently, the focus has been on the manufacture and distribution of various specific vaccines against this new virus, and the care of severely ill patients admitted to intensive care.
  
  
  CONCLUSIONS
  As this virus continues to infect new members of the global population, it may eventually become just one of the annual circulating seasonal influenza viruses. Until then, it will be prudent to continue to monitor it closely for any signs of enhanced transmissibility and virulence.
authors.affiliation: Department of Laboratory Medicine, National University of Singapore, Singapore. julian_wt_tang@nuhs.edu.sg
authors.forename: Julian W
authors.initials: JW
authors.lastname: Tang
authors.forename: Nandini
authors.initials: N
authors.lastname: Shetty
authors.forename: Tommy Tsan-Yuk
authors.initials: TT
authors.lastname: Lam
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000627:therapeutic use; D003140:Communicable Disease Control / Q000639:trends*; D004196:Disease Outbreaks / Q000517:prevention & control* / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D006801:Humans; D015994:Incidence; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects / Q000302:isolation & purification*; D007252:Influenza Vaccines / Q000008:administration & dosage*; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology; D008297:Male; D011322:Primary Prevention / Q000379:methods; D011634:Public Health; D018570:Risk Assessment; D016019:Survival Analysis; D013552:Swine; D016896:Treatment Outcome; D014611:Vaccination / Q000379:methods
chemical_list: D000998:Antiviral Agents; D007252:Influenza Vaccines