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. 2020 Dec 23;118(2):e2011548118. doi: 10.1073/pnas.2011548118

Table 1.

Parameter values used for simulations

Parameter Values Source
Mean intrinsic incubation period 5.5 d (33)
SD intrinsic incubation period 2.4 d (33)
Mean intrinsic generation interval 5.0 d (34)
SD intrinsic generation interval 1.9 d (34)

The intrinsic incubation period distribution is parameterized using a lognormal distribution with log mean μI=1.62 and log standard deviation σI=0.42. The intrinsic generation interval distribution is parameterized using a log-normal distribution with log mean μG=1.54 and log standard deviation σG=0.37. Log mean and log standard deviations represent the mean and standard deviations of the underlying normal distributions, which are later exponentiated. The joint probability distribution is modeled using a bivariate log-normal distribution with correlations (on the log scale) ρ={0,0.25,0.5,0.75}. The intrinsic incubation period and generation interval distributions are chosen to match characteristics of COVID-19 to illustrate realistic magnitudes of time-varying/perspective effects in the current pandemic.