Table 1.

Model parameter descriptions and values used for simulating the number of COVID-19 cases in Jordan.

Parameter and Symbols	Description	Scenario 1 Values
β (beta)	Describes the transmission rate	February 1 to March 17 = 0.37 March 18 to April 24 = 0.06 April 25 to May 15 = 0.20 After May 15 = 0.37
α (alpha)	Reduction in transmission rate. (Moderate to Severe)	0.5
ε (epsilon)	The incubation period from the state of exposure to the disease to become infectious	1/5.2
Ps	Probability of developing severe SAR-CoV-2 symptoms	0.01
µ (mu)	Recovery rate	1/14 days
R0	Basic Reproduction number	5.6

These parameters are as follows: Beta (β) describes the transmission rate and the spread of disease in the community. The β varies according to public health policies that are enforced or applied in communities such as pandemic containment, social distancing, remote working, closing schools, etc. Since Jordan’s culture is homogeneous, and people follow traditional forms for greeting, we have set the standard contact rate (β) to 0.37 [16,28,29]. To reflect the status of measures in Jordan, we added an extra layer (exception) to designate the non-pharmaceutical interventions (NPIs) that took place on March 17. As such, the contact rate value (β) was reduced from 0.37 to 0.06 [30] between March 17 and April 24. The contact rate value (β) was set to 0.2 between April 25 and May 15, reflecting the partial lifting of the curfew and partial reopening of selected businesses. After that, the contact rate value (β) was set to its original value of 0.37. Alpha (α) denotes the reduction in the transmission rate of hospitalized (moderate to severe) cases. We have used the value of α = 0.5 to reflect the negligible transmission rate of hospitalized patients. Epsilon (ε): the incubation period from the point of exposure to the disease becoming infectious. It is set to 5.2 days [9,10,31]. Ps: the probability of developing severe COVID-19 symptoms. This value was set at 0.01 [32]. Recovery rate (mu or µ), which indicates the time until an infectious case becomes recovered. Previous research [33] reports that the recovery time for COVID-19 is 14 days (µ = 1/14 days). Hence, we have used this value as the recovery rate (µ = 0.07) in our model. R₀: the reproduction number for COVID-19. Based on the above values, R₀ was calculated as 5.6 (see Supplementary Table S1 for formula). The basic reproduction number (R₀) measures the transmission (contagious) potential of COVID-19 and describes the average number of secondary infections caused by a typical primary infection in a completely susceptible population. An R₀ value of 5.6 was reported in other similar global simulations [34]. The literature reported that R₀ ranges between 2.3 and 6.5 [28,35,36,37] and a re-analysis of Chinese data provided an updated estimate of 5.7 (95% CI 3.8–8.9) [37]. Other published studies reported that, for social gathering events such as wedding parties in Jordan, the R₀ value was five [38].