“…The characteristics of the selected articles are listed in Supplementary Table S3 . Among the 60 estimates of transmission heterogeneity, four (6.7%) from two studies estimated the dispersion parameter ( k ) of SARS [16] , [18] , 11 (18.3%) from eight articles estimated the k for MERS [16] , [17] , [30] , [31] , [32] , [33] , [34] , [35] , and 45 (75.0%) from 17 articles estimated the k for COVID-19 [14] , [15] , [19] , [36] , [37] , [38] , [39] , [40] , [41] , [42] , [43] , [44] , [45] , [46] , [47] , [48] , [49] . Forty estimates (66.7%) were based on transmission pair data (i.e., offspring case number generated by each index case), and four estimates were calculated using epidemic/cluster size data.…”