Table 1

Demographic characteristic of the study population and data-based secondary

Demographic
characteristics
Index case
n (%)
Contacts of
index cases
n (%)
Contacts
positive
n (%)
Secondary
attack rate
% (95% CI)
Gender
 Female529 (23.87)5745 (48.65)84 (40.19)1.46 (1.17 to 1.82)
 Male1687 (76.13)6064 (51.35)125 (59.81)2.06 (1.73 to 2.46)
Age group (years)
0–936 (1.6)1553 (13.15)25 (11.96)1.61 (1.07 to 2.40)
10–19230 (10.38)1511 (12.80)26 (12.44)1.72 (1.14 to 2.55)
20–29665 (30.01)2471 (20.92)62 (29.67)2.51 (1.94 to 3.23)
30–39651 (29.38)2444 (20.70)51 (24.40)2.09 (1.57 to 2.76)
40–49309 (13.98)1741 (14.74)29 (13.88)1.67 (1.14 to 2.42)
50–59172 (7.76)1341 (11.36)15 (7.18)1.12 (0.65 to1.88)
 >60153 (6.9)748 (6.33)1 (0.48)0.13 (0.01 to 0.86)
 Evacuated to isolation centre
 No1946 (87.82)11 211 (94.94)199 (94.94)1.78 (1.55 to 2.04)
 Yes270 (12.18)598 (5.06)10 (5.06)1.67 (0.90 to 3.08)
Travelled in other countries
 Travelled246 (11.10)
 Not travelled1970 (88.90)
Relationship to index
 Household615 (5.21)18 (8.61)2.93 (1.84 to 4.60)
 Market/shop/pub9191 (77.83)146 (69.86)1.59 (1.35 to 1.86)
 Transport142 (1.20)3 (1.44)2.11 (0.67 to 6.43)
 Social1273 (10.78)27 (12.92)2.12 (1.46 to 0.31)
 Coworkers588 (4.98)15 (7.18)2.55 (1.54 to 4.19)
Had symptoms
 No symptoms11 531 (97.65)203 (97.13)1.74 (1.52 to 2.01)
 With symptoms278 (2.35)6 (2.87)3.73 (1.54 to 8.74)
Type of symptoms
 Fever9 (0.08)1 (0.48)11.11 (0.92 to 62.60)
 Difficulty breathing11 (0.09)00
 Runny nose18 (0.15)00
 Throat10 (0.08)00
 Cough237 (2.01)1 (0.48)0.42 (0.059 to 2.97)
 Chest pain40 (0.34)5 (2.39)12.5 (5.09 to 27.55)
 None11 484 (97.25)202 (96.65)1.76 (1.53 to 2.02)
 Total2216 (100)11 809 (100)209 (100)1.77 (1.55 to 2.02)