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] |