Volume 10, Number 7—July 2004
Model Parameters and Outbreak Control for SARS
|pa||Reduction in risk of infection for class S2||0.33|
|ρa||Initial proportion of the population at higher risk for SARS||0.77|
|βb||Transmission rate per day||0.25|
|1/ka||Mean incubation period (days)||6.37|
|1/γ1||Mean infectious period (days)||28.4|
|1/γ2a||Mean infectious period for persons with diagnosed SARS (days)||23.5|
|1/α||Mean period before diagnosis (days)||4.85|
|δa||Induced death rate per day||0.0279|
|q||Relative measure of infectiousness for the exposed class||0.1|
|lc||Relative infectiousness after isolation has begun||[0,1]|
aBaseline values for k, γ2, α, ρ, p and δ have been taken from reference 3.
bβ = 0.25 is our estimated transmission rate in Hong Kong.
cl = 0 means perfect isolation, while l = 1 means no isolation.
1At the time this work was carried out, Dr. Castillo-Chavez was on sabbatical at Los Alamos National Laboratory and faculty of Cornell University.
2Recall that l = 0 corresponds to complete isolation, whereas l = 1 means no effective isolation occurs. Hence, a decrease in l means an increase in the effective isolation of the infected persons.