Table 1

Demographic characteristics of the study population at eight time points

29 March 20201 April 20204 April 20207 April 202010 April 202013 April 202016 April 202019 April 2020All unique users
N1 324 8431 431 5151 142 9231 083 601995 157985 860980 6081 164 2621 960 242
Predicted COVID-19 (n/%)60 82779 37862 50848 41830 13222 35216 58615 991117 614
(4.6)(5.6)(5.5)(4.5)(3.0)(2.3)(1.7)(1.4)(6.0)
Average number of reports per user2.93.84.24.75554.54.4
Age, years (median (IQR))41 (21)41 (21)43 (21)44 (22)45 (21)45 (21)46 (21)45 (21)42.2 (21.8)
Male, (n/%)426 923459 620365 078353 233327 608327 620327 114388 378654 950
(32.2)(32.1)(31.9)(32.6)(32.9)(33.3)(33.3)(33.4)(33.4)
Obesity, %21.321.420.720.321.622.121.421.721.5
Kidney disease, %0.50.50.50.50.50.60.60.60.5
Lung disease, %12.212.312.512.512.412.412.412.412.2
Diabetes, %2.42.52.72.72.82.92.92.92.4
Smokers, %10.510.59.79.49.08.88.79.010.4
Heartdisease, %1.41.41.61.61.71.71.71.71.4
  • Obesity: BMI >=30 kg/m2.

  • At each time point, we only include users who have made an assessment in the previous 7 days. Exclusion criteria are listed in the supplements. Users are asked daily whether (or not) they have any symptoms. Predicted COVID-19 was calculated on users who reported on symptoms. Users who reported having no symptoms were included in the area-level predicted prevalence estimates (please see the supplements for details).

  • BMI, body mass index.