Table 2 Characteristics of participants in the different stages of the study

Eligible participants

Participants who agreed to receive the SMS

Participants who completed the baseline questionnaire

Participants who agreed to be followed-up

Participants contacted for the first follow-up questionnaire

Participants who completed the first follow-up questionnaire

Participants in the first follow-up who agreed to participate in the second follow-up

National contact tracing data

Study data

Study data

n = 225,119

n = 66,645

n = 10,708

n = 8,438

n = 3,240 (remaining 5,198 participants will be contacted after 01/11/21)

n = 2,101

n = 1,659

Age groups, n (%)

 •18–25

42,048 (18.7)

14,132 (21.2)

1,660 (15.5)

1,047 (12.4)

518 (16.0)

282 (13.4)

189 (11.4)

 •26–45

102,346 (45.5)

31,894 (47.9)

5,130 (47.9)

4,076 (48.3)

1,527 (47.1)

1,010 (48.0)

785 (47.3) 

 •46–65

60,742 (27.0)

17,860 (26.8)

3,534 (33.0)

2,978 (35.3)

1,111 (34.3)

760 (36.3)

643 (38.7)

 •66 85

17,549 (7.8)

2,672 (4.0)

374 (3.5)

329 (3.9)

81 (2.5)

47 (2.2)

42 (2.5)

 •86 + 

2,434 (1.0)

87 (0.1)

10 (0.1)

8 (0.1)

3 (0.1)

2 (0.1)

0 (0.0)

 Sex, women, n (%)

120,031 (53.3)

35,624 (53.4)

6,489 (60.6)

5,213 (61.8)

1,950 (60.2)

1,315 (62.6)

1,075 (64.8)

 At least one acute COVID-19 symptom, n (%)

178,040 (79.1)

56,046 (84.1)

9,894 (92.4)

7,754 (91.9)

Persistent symptoms, n (%)

 •0

1,093 (52.0)

576 (34.7)

 •1

274 (13.0)

328 (19.7)

 •2

233 (11.1)

302 (18.2)

 •3

132 (6.3)

152 (9.2)

 •4 or more

369 (17.6)

301 (18.2)