Table 1 Parameter settings in the SEIHR(Q) model
Parameter and definition | Value | Source and Explanation |
|---|---|---|
c: Contact rate | 14.5 | Prior to the implementation of the Level-1 emergency response on January 23 [13, 24], the contact rate was approximately 14.5 [25]. After that, the contact rate dropped dramatically and stabilized at a low rate of 4. Since the resumption of work, the value has gone up gradually. |
β: Probability of transmission | 0.035 | The reproduction number R can be calculated as the transmission rate multiplied by the transmission time, which in this model is βc/σ. In Wuhan, the initial R0 was estimated to be approximately 2.67 [26, 27]. Therefore, β can be calculated to be 0.035 |
σ: Transition rate | 0.19 | |
q: Quarantined rate of exposed individuals | 0 | Initialized as 0 and gradually increased to 0.7 as Level-1 emergency response was implemented [11, 13]. |
λ: Rate of return from Sq to S | 1/14 | Estimated based on the recommendation of the Shanghai Municipal Health Commission [31]. |
δI: Transition rate of individuals in I to the hospitalized group | 0.12 | The initial value taken from the reference [11] quickly dropped due to abundant medical resources in Wuhan and the acceleration of nucleic acid testing. |
δH: Transition rate of individuals in Iq to the hospitalized group | 1 | Quarantined infected individuals were admitted to the hospital immediately after nucleic acid testing. |
μ: Isolation rate of patients at fever clinics | 0 | No isolation at a fever clinic in Wuhan at the beginning. With the policy of stricter isolation at fever clinics, the value increased to 0.4 and then 0.7 [32]. |
γI: Recovery rate of individuals in I | 0.07 | Individuals with mild symptoms or an asymptomatic infection recovered within 14 days on average [11, 12]. |
γH: Recovery rate of individuals in H | 0.01 | Model calibration |
αI,αH: Death rate | 0.004 | Model calibration |
θ: Infectious weight in incubation period | 0.5 | |
q: Percentage of close contacts who are quarantined | 0 | Initialized as 0 and gradually increased to 0.7 as Level-1 emergency response was implemented [13, 32].. |