Urban Household Transmission of SARS-CoV-2 During Periods of High and Low Community Transmission

Factors Associated With Household Transmission of SARS-CoV-2

“…Compared with the SAR for 28 studies 12,14,17,27,94 from January to February 2020 (13.4%; 95% CI, 10.7%-16.7%), the SAR was significantly higher for 30 studies 6,7,15,16,19,22,25,26,28,30,[68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83][84][85][86]93 from March to April 2020 (19.4%; 95% CI, 15.2%-24.5%; P = .03) and 15 studies 5,8,10,18,20,21,23,24,29,31,32,35,37,38,40 from July 2020 to March 2021 (31.1%; 95% CI, 22.6%-41.1%; P < .001) but not significantly different from the SAR for 14 studies…”

“…To elucidate factors associated with differences in SAR, we explored attributes of studies from the periods with the lowest and highest household SARs. Among 28 studies 12,14,17,27,94 from January to February 2020 and 15 studies 5,8,10,18,20,21,23,24,29,31,32,35,37,38,40 from July 2020 to March 2021, 6 studies 12,46,54,57,59,62 (21.4%) and 4 studies 8,10,20,23 (25.0%), respectively, reported testing contacts at least twice, 1 study 46 (3.6%) and 3 studies 5,8,23 (18.8%) reported following contacts for longer than 14 days, 1 study 45 (3.6%) and 6 studies 8,23,24,29,37,40 (33.3%) were published as preprints, 21 studies 12,14,27,46,[48][49][50]…”

“…The estimated overall household SAR for all 87 studies was 18.9% (95% CI, 16.2%-22.0%), with significant heterogeneity ( I 2 = 99.4%; P < .001) ( Figure 2 ). Excluding studies with only asymptomatic 85 or pediatric 36 , 66 index cases, studies that tested only 7 , 9 , 15 , 17 , 19 , 24 , 26 , 29 , 30 , 31 , 35 , 37 , 45 , 47 , 61 , 65 , 68 , 69 , 71 , 77 , 79 , 81 , 82 , 86 , 87 , 90 , 92 , 94 or asymptomatic 78 contacts, studies with long follow-up periods (≥21 days), 5 , 8 , 9 , 23 , 46 , 92 and studies published as preprints, 8 , 23 , 24 , 29 , 45 , 79 , 88 , 89 , 90 , 92 the overall SAR among the 47 remaining studies 4 , 6 , 10 , 11 , 12 , 13 , 14 , …”

“…To elucidate factors associated with differences in SAR, we explored attributes of studies from the periods with the lowest and highest household SARs. Among 28 studies 12 , 14 , 17 , 27 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 94 from January to February 2020 and 15 studies 5 , 8 , 10 , 18 , 20 , 21 , 23 , 24 , 29 , 31 , 32 , 35 , 37 , 38 , 40 from July 2020 to March 2021, 6 studies 12 , 46 , 54 , 57 , 59 , 62 (21.4%) and 4 studies 8 , 10 , 20 , 23 (25.0%), respectively, reported testing contacts at least twice, 1 study 46 (3.6%) and 3 studies 5 , 8 , 23 (18.8%) reported following ...…”

“…Characteristics of Studies Included in Analysis of Household Secondary Attack Rates for SARS-CoV-2 (continued) ,23,24,29,37,40,45,79,[88][89][90]92 21.0(13.8-30.6) No 75[4][5][6][7][9][10][11][12][13][14][15][16][17][18][19][20][21][22][25][26][27][28][30][31][32][33][34][35][36][37][38][39][74][75][76][77][78][80][81][82][83][84]…”