Table 1 The summary of the dispersion parameter, k, estimates of COVID-19 transmission in the existing literature and this study. The highlighted estimates are considered as main results in this study
| type of dataset | data source | truncation | dispersion parameter, k | estimated in | sporadic case included |
|---|---|---|---|---|---|
| offspring # of each case | Dataset #1: Xu et al. [8] (n = 2214) | No | 0.70 (0.59, 0.98) | He et al. [12] | No |
| 0.72 (0.63, 0.89) | this study | ||||
| Yes | 0.37 (0.29, 0.48) | ||||
|
Dataset #2: Adam et al. [11] (n = 290) | No | 0.43 (0.29, 0.67) | Adam et al. [11] | Yes | |
| 0.42 (0.26, 0.78) | this study | ||||
| Yes | 0.32 (0.15, 0.64) | No | |||
|
Dataset #3: Zhang et al. [13] (n = 47) | No | 0.25 (0.13, 0.88) | Zhang et al. [13] | Yes | |
| 0.22 (0.03, 1.15) | this study | ||||
| Yes | 0.18 (0.01, 1.79) | No | |||
| not included in this study | No | 0.58 (0.35, 1.18) | Bi et al. [34] | Yes | |
| range: 0.32–0.82 | Lau et al. [22] | ||||
| 0.11 (0.05, 0.25) | Tariq et al. [35] | ||||
| outbreak size | not applicable | 0.54 (0.01, 6.95) | Riou et al. [3] | irrelevant | |
| 0.10 (0.05, 0.20) | Endo et al. [36] | ||||
| genome sequences | 0.32 (0.13, 0.38) | Wang et al. [37] |