Research Article

Investigation of Factors Affecting COVID-19 and Sixth Wave Management Using a System Dynamics Approach

Table 10

Variables, parameters, and formulation of the model.

VariablesTypeFormulas

SusceptibleLevelINTEG (-infecting-vaccination rate, initial population)
ExposedLevelINTEG (-infecting-vaccination rate, initial population)
InfectedLevelINTEG (Advancing + importing infected-dying-Recovering, 416)
RecoveredLevelINTEG (Recovering,355)
DeathsLevelINTEG (Dying,24)
Vaccinated peopleLevelINTEG (vaccination rate, 40)
InfectingRateActive Infected  Transmission rate
AdvancingRateExposed/Incubation time
RecoveringRateInfected/Infection Duration  (1-Fatality rate)
DyingRateInfected  Fatality Rate/Infection duration
Vaccination rateRate((2+Vaccine import)   vaccine availability  (1+people thinking pressure)  (1 + Booster Dose))/(1 + fraction infected)
Admission durationExogenous10
Available personnelExogenous180
People thinking pressureExogenous0.3
Vaccine importExogenous0.6
Booster doseEndogenosSTEP(0.1, 120)+STEP(0.2, 150)+STEP(0.4, 210)
Vaccine availabilityExogenous0.9
Income supportExogenous50
Economic strainEndogenos1-(Income Support/500)
Vaccination effect on reduce R0Exogenous0.3
Working place closing total recoveredExogenous100
Total recoveredEndogenosVaccinated People + recovered
Fraction susceptibleEndogenosSusceptible/Initial population
Initial populationEndogenos84000-(0.0001  (total recovered-deaths))
Active infectedEndogenosInfected  (1-Isolation effectiveness)
Behavior reaction timeExogenous20
Behavioral risk reductionExogenous0.1
Contact density declineExogenous0
Fatality rateEndogenosUntreated fatality Rate + (Treated fatality rate-untreated fatality rate)/(1 + Hospital Strain^ hospital capacity sensitivity)
FINAL TIMEExogenous210
Fraction infectedEndogenosInfected/Susceptible
Fraction requiring hospitalizationExogenous0.1
Untreated Fatality rateExogenous0.04
Treated Fatality rateExogenous0.01
Transmission rateEndogenos(Initial uncontrolled transmission Rate  Relative behavioral Risk  Fraction susceptible   relative contact Density  (1-working place closing/1000))
TIME STEPExogenous0.125
Serious casesExogenousInfected  Fraction requiring hospitalization
Relative contact densityEndogenos(1 + economic strain)/(1 + Contact density Decline  (1-Fraction susceptible))
Relative behavioral riskEndogenosSMOOTH3(1-STEP(Behavioral risk reduction, import Time),Behavior reaction time)
R0Endogenos3.3-STEP(3.3  Vaccination effect on reduce R0, 40)
Public health strainEndogenosInfected/Public health capacity
Public HealthCapacity sensitivityExogenous2
Public health capacityExogenous1000
Potential Isolation effectivenessExogenous0
N Imported infectionsExogenous3
Isolation reaction timeExogenous2
Isolation effectivenessEndogenosSMOOTH3(STEP(Potential Isolation effectiveness, import Time), Isolation reaction Time)/(1 + Public health Strain^ public health capacity sensitivity)
Initial uncontrolled transmission rateEndogenosR0/Infection duration
Initial timeExogenous0
Infection durationExogenous10
Incubation timeExogenous5
Importing infectedEndogenosN Imported Infections  PULSE(Import time, TIME STEP)/TIME STEP
Import timeExogenous10
Hospital strainEndogenous(Serious Cases  Admission duration/(Hospital Capacity  Available personnel))
Hospital capacity sensitivityExogenous2
Hospital capacityExogenous137