title: Influenza.
abstract: BACKGROUND
  During the autumn-winter months (influenza seasons), influenza circulates more frequently, causing a greater proportion of influenza-like illness, and sometimes serious seasonal epidemics. The incidence of infection depends on the underlying immunity of the population.
  
  
  METHODS
  We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of vaccines to prevent influenza? What are the effects of antiviral chemoprophylaxis of influenza? What are the effects of antiviral medications to treat influenza? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2008 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
  
  
  RESULTS
  We found 21 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
  
  
  CONCLUSIONS
  In this systematic review we present information relating to the effectiveness and safety of the following interventions: vaccines, amantadine, oseltamivir, zanamivir, rimantadine.
authors.affiliation: Cochrane Vaccines Field, Rome, Italy.
authors.forename: Tom
authors.initials: T
authors.lastname: Jefferson
mesh_terms: D000208:Acute Disease; D000280:Administration, Inhalation; D006801:Humans; D015994:Incidence; D007252:Influenza Vaccines / Q000627:therapeutic use; D007251:Influenza, Human / Q000188:drug therapy; D053139:Oseltamivir / Q000627:therapeutic use; D012299:Rimantadine / Q000627:therapeutic use; D053243:Zanamivir / Q000627:therapeutic use
chemical_list: D007252:Influenza Vaccines; D012299:Rimantadine; D053139:Oseltamivir; D053243:Zanamivir