title: Estimated impact of aggressive empirical antiviral treatment in containing an outbreak of pandemic influenza H1N1 in an isolated First Nations community.
abstract: BACKGROUND
  The 2009 influenza A (H1N1) pandemic was mild by historical standards, but was more severe in isolated Canadian Indigenous communities. Oseltamivir was used aggressively for outbreak control in an isolated northern Ontario First Nations community. We used mathematical modeling to quantify the impact of antiviral therapy on the course of this outbreak.
  
  
  METHODS
  We used both a Richards growth model and a compartmental model to evaluate the characteristics of the outbreak based on both respiratory visits and influenza-like illness counts. Estimates of best-fit model parameters, including basic reproductive number (R0 ) and antiviral efficacy, and simulations, were used to estimate the impact of antiviral drugs compared to social distancing interventions alone.
  
  
  RESULTS
  Using both approaches, we found that a rapidly growing outbreak slowed markedly with aggressive antiviral therapy. Richards model turning points occurred within 24 hours of antiviral implementation. Compartmental models estimated antiviral efficacy at 70-95%. Plausible estimates of R from both modeling approaches ranged from 4·0 to 15·8, higher than published estimates for southern Canada; utilization of aggressive antiviral therapy in this community prevented 962-1757 cases of symptomatic influenza and as many as 114 medical evacuations in this community.
  
  
  CONCLUSIONS
  Although not advocated in other settings in Canada, aggressive antiviral therapy markedly reduced the impact of a pandemic-related influenza A (H1N1) outbreak in an isolated Canadian First Nations community in northern Ontario, Canada. The differential risk experienced by such communities makes tailored interventions that consider risk and lack of access to medical services, appropriate.
authors.affiliation: Department of Applied Mathematics, University of Western Ontario, London, ON, Canada.
authors.forename: Yanyu
authors.initials: Y
authors.lastname: Xiao
authors.forename: Zeenat
authors.initials: Z
authors.lastname: Patel
authors.forename: Adam
authors.initials: A
authors.lastname: Fiddler
authors.forename: Lilian
authors.initials: L
authors.lastname: Yuan
authors.forename: Marie-Elaine
authors.initials: ME
authors.lastname: Delvin
authors.forename: David N
authors.initials: DN
authors.lastname: Fisman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000998:Antiviral Agents / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D003140:Communicable Disease Control / Q000379:methods; D003198:Computer Simulation; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000188:drug therapy* / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D009864:Ontario / Q000453:epidemiology; D053139:Oseltamivir / Q000627:therapeutic use*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000998:Antiviral Agents; D053139:Oseltamivir
keywords: Epidemiology; Indigenous health; influenza; mathematical modeling; oseltamivir