Predictability and epidemic pathways in global outbreaks of infectious diseases: the SARS case study

Table 1 Parameter values

Parameter	Description		Baseline value
T ₀	Initial offset from 21 February (days)		3*
β	Rate of transmission		0.57*
L(t = 0)	Number of initial latent individuals		10*
		21 February + T ₀-20 March	1.00
s _f(t)	Scaling factor for the rate of transmission	21 March – 9 April	0.37
		10 April – 11 July	0.06
r _β	Relative infectiousness of patients at the hospital		0.2
ε ^-1	Average latency period (days)		4.6
		21 February + T ₀-25 March	4.84
μ ^-1(t)	Average period from onset of symptoms to admission (days)	25 March – 1 April	3.83
		2 April – 11 July	3.67
μ _R ^-1	Average period from admission to recovery (days)		23.5
μ _D ^-1	Average period from admission to death (days)		35.9
d	Case fatality rate		0.2

Baseline values for all epidemiological parameters and initial conditions. Parameters marked with an asterisk (*) are estimated by our model through the fitting procedure described in the main text. The three successive decreasing values for the μ ^-1model are the prompter, identification and subsequent isolation of infectious individuals [11]. A step function is also assumed for the scaling factor s _f(t) of the transmission parameter β, with values taken from the estimates of the effective reproductive number R _twith respect to R ₀ during the early stage of SARS epidemic in Hong Kong [9]. This corresponds to the effective reduction of the reproductive number due to the application of control measures [9].