title: Influenza antiviral prescribing practices during the 2007-08 and 2008-09 influenza seasons in the setting of increased resistance to oseltamivir among circulating influenza viruses.
abstract: BACKGROUND
  In December 2008, new interim guidelines on the use of influenza antiviral agents were released in response to a high prevalence of circulating oseltamivir-resistant seasonal influenza A(H1N1) and adamantane-resistant influenza A(H3N2) viruses. Zanamivir, oseltamivir +/- an adamantane, or oseltamivir was recommended, depending on virus type, subtype, and local surveillance data.
  
  
  METHODS
  Information about antiviral prescribing practices among IDSA Emerging Infections Network (EIN) members was obtained using two web-based questionnaires; one in January 2009 regarding the prior 2007-08 influenza season and one in April 2009 (prepandemic), regarding the concurrent 2008-09 season.
  
  
  RESULTS
  In the 2007-08 survey, 646 (52%) of 1249 EIN members responded and in the 2008-09 season survey, 350 (27%) of 1281 responded. In 2008-09 vs. 2007-08: 59% vs. 69% prescribed or recommended antivirals for treatment (p<.0001); 48% vs. 80% prescribed oseltamivir alone and 39% vs. 10% prescribed zanamivir alone (p<.0001 for both). During 2008-09 28% reported treating fewer patients compared with 2007-08; 42% felt antivirals were less effective due to resistance and 40% felt patients had less severe illness. During 2008-09, 42% of respondents reported difficulty providing zanamivir to patients vs. 5% for oseltamivir (p<.0001). Only 11% of respondents could test for influenza A subtype. During both seasons, ~55% used local surveillance data to make treatment decisions.
  
  
  CONCLUSIONS
  A mild winter influenza season, difficulty obtaining recommended agents, and lack of access to subtype diagnosis and surveillance data may have contributed to reduced antiviral use during 2008-09.
authors.affiliation: Epidemic Intelligence Service, Office of Workforce and Career Development assigned to Influenza Division, Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA 30333, USA. nila.dharan@nyumc.org
authors.forename: Nila J
authors.initials: NJ
authors.lastname: Dharan
authors.forename: Susan E
authors.initials: SE
authors.lastname: Beekmann
authors.forename: Anthony
authors.initials: A
authors.lastname: Fiore
authors.forename: Lyn
authors.initials: L
authors.lastname: Finelli
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Uyeki
authors.forename: Philip M
authors.initials: PM
authors.lastname: Polgreen
authors.forename: Alicia M
authors.initials: AM
authors.lastname: Fry
mesh_terms: D000218:Adamantane / Q000494:pharmacology / Q000627:therapeutic use; D000998:Antiviral Agents / Q000494:pharmacology / Q000627:therapeutic use*; D004196:Disease Outbreaks; D024882:Drug Resistance, Viral; D004363:Drug Utilization; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects; D053122:Influenza A Virus, H3N2 Subtype / Q000187:drug effects; D007251:Influenza, Human / Q000188:drug therapy* / Q000453:epidemiology / Q000821:virology; D053139:Oseltamivir / Q000494:pharmacology / Q000627:therapeutic use; D017410:Practice Guidelines as Topic; D010818:Practice Patterns, Physicians'; D012189:Retrospective Studies; D012299:Rimantadine / Q000494:pharmacology / Q000627:therapeutic use; D012621:Seasons; D011795:Surveys and Questionnaires; D053243:Zanamivir / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D000998:Antiviral Agents; D012299:Rimantadine; D053139:Oseltamivir; D053243:Zanamivir; D000218:Adamantane