Volume 27, Number 3—March 2021
Research
Daily Forecasting of Regional Epidemics of Coronavirus Disease with Bayesian Uncertainty Quantification, United States
Table 3
Parameter | Definition |
---|---|
S0 | Initial size of susceptible population* |
I0 | Initial no. infected individuals† |
n | No. prior social distancing periods (e.g., 0 or 1) |
mb | Protective effect of social distancing‡ |
ρE | Relative infectiousness of an exposed person without symptoms during the incubation period§ |
ρA | Relative infectiousness of an asymptomatic person in the immune clearance phase of infection§ |
kL | Rate constant for progression through each stage of the incubation period¶ |
kQ | Rate constant for entry into quarantine for a person without symptoms |
jQ | Rate constant for entry into quarantine for a person with mild symptoms |
fA | Fraction of all cases that are asymptomatic |
fH | Fraction of all cases of severe disease (including patients requiring hospitalization or isolation at home) |
fR | Fraction of persons with severe disease who eventually recover |
cA | Rate constant for recovery of asymptomatic persons in the immune clearance phase of infection |
cI | Rate constant for recovery of symptomatic persons with mild disease or progression to severe disease# |
cH | Rate constant for recovery of symptomatic persons with severe disease or progression to death** |
*Initial susceptible population within a given region is assumed to be the total regional population. †Assuming that there is initially a single infected, symptomatic person. ‡This parameter defines the reduction in disease transmission caused by the protective effects of social distancing. §This parameter characterizes infectiousness relative to a symptomatic person with all other factors being equal (i.e., a symptomatic person exhibiting the same social distancing behavior). ¶The incubation period is divided into 5 stages, each of equal duration on average. #In the model, after a mean waiting time of 1/cI, symptomatic persons with mild disease recover or progress to severe disease. **In the model, after a mean waiting time of 1/cH, symptomatic persons with severe disease recover or die.