title: Long-term use of oseltamivir for the prophylaxis of influenza in a vaccinated frail older population.
abstract: OBJECTIVE
  To investigate the efficacy of once-daily oral oseltamivir for 6 weeks (Tamiflu) in prophylaxis against laboratory-confirmed clinical influenza in frail older subjects living in homes for seniors and to determine the safety and tolerability of long-term oseltamivir.
  
  
  METHODS
  Double-blind, placebo-controlled, parallel-group, randomized, multicenter study.
  
  
  METHODS
  Thirty-one residential homes for seniors across United States and Europe.
  
  
  METHODS
  Five hundred forty-eight frail older occupants (mean age 81 years, >80% vaccinated).
  
  
  METHODS
  Prophylaxis with oseltamivir 75 mg or placebo once daily for 6 weeks, beginning when influenza was detected locally.
  
  
  METHODS
  The primary efficacy endpoint was laboratory-confirmed clinical influenza.
  
  
  RESULTS
  Oseltamivir administration resulted in a 92% reduction in the incidence of laboratory-confirmed clinical influenza compared with placebo (placebo 12/272 (4.4%), oseltamivir 1/276 (0.4%); P = .002). Of subjects vaccinated against influenza, oseltamivir was 91% effective in preventing laboratory-confirmed clinical influenza (placebo 11/218 (5.0%), oseltamivir 1/222 (0.5%); P = .003). Oseltamivir use was associated with a significant reduction in the incidence of secondary complications (placebo 7/272 (2.6%), oseltamivir 1/276 (0.4%); P = .037). Although nearly all subjects were taking concomitant medication both before and during the study, oseltamivir was well tolerated. A similar incidence of adverse events, including gastrointestinal effects, occurred in both groups. There was no suppression of antibody response in oseltamivir recipients.
  
  
  CONCLUSIONS
  Oral oseltamivir 75 mg once daily for 6 weeks effectively prevented clinical influenza in vaccinated frail older subjects using significant concomitant medications in a residential care setting. The treatment was well tolerated and provided additional protection to that afforded by vaccination.
authors.affiliation: Protocare Trials at the San Antonio Center for Clinical Research, San Antonio, Texas, USA.
authors.forename: P H
authors.initials: PH
authors.lastname: Peters
authors.forename: S
authors.initials: S
authors.lastname: Gravenstein
authors.forename: P
authors.initials: P
authors.lastname: Norwood
authors.forename: V
authors.initials: V
authors.lastname: De Bock
authors.forename: A
authors.initials: A
authors.lastname: Van Couter
authors.forename: M
authors.initials: M
authors.lastname: Gibbens
authors.forename: T A
authors.initials: TA
authors.lastname: von Planta
authors.forename: P
authors.initials: P
authors.lastname: Ward
mesh_terms: D000081:Acetamides / Q000009:adverse effects / Q000627:therapeutic use*; D000368:Aged; D000369:Aged, 80 and over; D000998:Antiviral Agents / Q000009:adverse effects / Q000627:therapeutic use*; D004311:Double-Blind Method; D005060:Europe / Q000453:epidemiology; D005260:Female; D016330:Frail Elderly; D006707:Homes for the Aged; D006801:Humans; D007251:Influenza, Human / Q000453:epidemiology / Q000517:prevention & control*; D008297:Male; D009439:Neuraminidase / Q000037:antagonists & inhibitors*; D053139:Oseltamivir; D014481:United States / Q000453:epidemiology
chemical_list: D000081:Acetamides; D000998:Antiviral Agents; D053139:Oseltamivir; D009439:Neuraminidase