# SIR Economic Model

[Susceptible; Infected; Recovered]
:: Beta Test - Not for Official Use ::
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:: You can change parameter values in yellow boxes below ::
DATA ENTRY PAGE
 Group A Group B Treat_A Prevention Cost Treat_B Prevention Cost Total Population QOL loss per Pt Sick Day (or Unit of Time) Maximum WTP Per Effect -->>

 Group A Group B Beta Rate per 100 Infection Rate Rate per 100 Infection Rate Gamma Rate per 100 Recovery Rate Rate per 100 Recovery Rate Alpha Rate per 100 Inoculation rate Rate per 100 Inoculation Rate Delta Rate per 100 "Herd protection" factor Rate per 100 "Herd protection" factor Rho Rate per 100 "Hygiene" factor Rate per 100 "Hygiene" factor

 SAMPLE GRAPHICS FROM RESULTS PAGE SIR Econ Model :: Susceptible, Infected, Recovered  SIR Graph A SIR Graph B  Inc. Cost Effectiveness Ratio Inc. Net Beneft vs WTP (c) HDS

 SIR MODEL CONSIDERATIONS A classic model for exploring the spread of infectious diseases is the SIR model. It is sometimes considered in the examination of the "diffusion of innovation". The SIR model evaluates the fractions of the population which are: (S)usceptible (I)nfected (R)ecovered The SIR mathematical approach below is based on the Kermack–McKendrick model: [Formulas require additional beta testing.] dS/dT = S' = - beta * SI - alpha*SR beta = "infection" rate. alpha = "inoculation" rate dI/dT = I' = +(1-rho)* beta*SI - gamma*I - delta*IR gamma = "recovery" rate. delta = "herd" effect dR/dT = R' = +rho*beta*SI + gamma*I + alpha*SR + delta*IR rho = "hygiene" factor Note: S + I + R= 1 and S' + I' + R'= 0. :: Transitions from S to I occur when these groups of individuals interact. :: Transitions from I to R occur when infected individuals recover (or expire).

Resources:
(1) Weisstein, Eric W. "Kermack-McKendrick Model."
From MathWorld--A Wolfram Web Resource. http://mathworld.wolfram.com/Kermack-McKendrickModel.html
(2) SIR Model -- http://www.docstoc.com/docs/104243450/SIR-Model
(3) SIR Model Seminar -- http://www.bluffton.edu/mat/dept/seminar_docs

(c) Health Decision Strategies, LLC
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