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Table 1 Variables and parameters of the model

From: Potential for international spread of wild poliovirus via travelers

Variable Biological description Sources
S i (t) Number of susceptible individuals in country i at time t Calculated from the total population in country i at year t times the probability of not being vaccinated
I i (t) Number of polio cases in country i at time t Calculated from the model
p i (t) Prevalence of polio in country i at time t Calculated from the model
Parameter Biological description  
λ i (t) Force of infection in country i at time t Calculated from the number of reported cases in country i at year t
1/μ i Life expectancy of population in country i [26]
1/γ i Average duration of infection in country i Reference [14]