Table 1: State variables, parameters and definitions. Initial values of state variables, principal parameter values and definitions of principal variables. See Figure 1 for state variables. Relevant equation numbers are given.

State variable initial values (t = 0)Units

𝑛 s u s = 𝑛 c i t y 𝑛 i n f 1 𝑛 r e c SusceptiblesPersons
𝑛 i n f 1 = 1 InfectedsPersons
𝑛 r e c = 0 usually, but see Figure 3(c)Recovered (immune)Persons
All other 𝑛 x x x , 𝑛 x x x x = 0 (Figure 1)Persons, viruses
Parameters + valueDescriptionUnits

𝑓 a s y = 0 . 9 Asymptomatic fraction (3)
𝑓 h o s = 0 . 0 5 Fraction of sick hospitalized (4)
𝑘 a s y = 2 Transfer rate (7)Day−1
𝑘 d e l = 1 0 / 1 0 9 5 (see 𝜏 i m m below)Transfer rate (11)Day−1
𝑘 h o s = 2 Transfer rate (8)Day−1
𝑘 i n f = 2 Transfer rate (3)Day−1
𝑘 r e c = 0 ( o r 1 ) Rate constant (10)Day−1
𝑘 s i c = 2 Transfer rate (4)Day−1
𝑘 v i r = 2 0 0 Virus production parameter (13)Virus units person−1 day−1
𝑘 v i r , d n m = 5 Virus natural mortality (15)Day−1
𝑛 c i t y = 1 0 6 Population of city (see 1st line of table, paragraph before (1), and paragraph after (2))Persons
𝑅 0 = 4.78 by (20)Basic reproductive ratio

β = 0.1Infection transmission rate (2)Persons (virus units)−1 day−1
𝜇 = 1 / ( 6 0 × 3 6 5 ) = 4 . 5 6 6 × 1 0 5 Natural birth/death rate (2)Day−1
𝜇 h o s = 0 . 0 0 1 Flu-induced death rate (hospital) (8)Day−1
𝜇 s i c = 0 . 0 0 1 Flu-induced death rate (home) (4)Day−1
𝜏 g e n = 2 . 5 1 ((B.7); see 2nd paragraph after (22))Generation timeDay−1
𝜏 i m m = 3 × 3 6 5 = 1 0 9 5 Loss of immunity delay (11)Day
Environmental parametersDescriptionUnits

𝑞 T = 2 Temperature exponent (18)
𝑠 e n v = 0 (1)Environment switch (18)
𝑇 a i r 0 = 1 3 Temperature threshold (18) °C
𝑘 T a i r = 0 . 1 Scaling factor (18)(°C)−2 d 1
VariablesDescriptionUnits

𝑘 h o s Hospital admission rate (5)Persons day−1
𝑘 v i r , e n v Environmentally induced death rate ((18), (15))Day−1
𝑅 0 Basic reproductive ratio (20)
𝑠 i n f Infectious strength (virus production rate) (13)Virus person−1 day−1