Retrospective study identifies infection related risk factors in close contacts during COVID-19 epidemic

Abstract

This study aimed to compare the risk of infection of children with that of adults and to explore risk factors of infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) by following up close contacts of COVID-19 patients. Method: The retrospective cohort study was performed among close contacts of index cases diagnosed with COVID-19 in Guangzhou, China. Demographic characteristics, clinical symptoms and exposure information were extracted. Logistic regression analysis was employed to explore the risk factors. The restricted cubic spline was conducted to examine to the dose-response relationship between age and SARS-CoV-2 infection. Results: The secondary attack rate (SAR) was 4.4% in 1,344 close contacts. The group of household contacts (17.2%) had the highest SAR. The rare-frequency contact (p < 0.001) and moderate-frequency contact (p < 0.001) were associated with lower risk of infection. Exposure to index cases with dry cough symptoms was associated with infection in close contacts (p = 0.004). Compared with children, adults had a significantly increased risk of infection (p = 0.014). There is a linear positive correlation between age and infection (p = 0.001). Conclusions: Children are probably less susceptible to COVID-19. Close contacts with frequent contact with patients and those exposed to patients with cough symptoms are associated with an increased risk of infection.

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 , …”

“…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]…”

Differences in Psychological and Behavioral Changes between Children following School Closure due to COVID-19

“…Children in the lower grade elementary school group had more psychological reactions such as crying easily, complaining, difficulty in keeping calm, and dependency on parents and family than those in other groups. Although children have a lower rate of COVID-19 infection and less severe clinical manifestations compared to adults, psychological problems are more serious in them, especially in younger children [ 10 ]. In addition, we found that children in lower grades had more difficulty in understanding COVID-19 infection and the necessity of restrictions due to COVID-19 compared to older children.…”