Table I.
Overall demographics and results for the eight cohorts studied
| Country | N of samples | % female | Age in years (mean, range) | Date of first nationally recorded case of COVID-19 | Sample collection date range | N with clinical symptoms | N with positive PCR results | Proportion with positive PCR results | Proportion of cohort with symptoms | If symptomatic, time between symptom onset and blood test | N seropositive | seroprevalence rate (95% CI) | National COVID-19 rate/100,000 population at time of sampling |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Austria | 196 | 84.2 | 38, 22–65 | 25/02/2020 | 17–24/07/20 | 33 | 0 | 0 | 16.8 | 116 days | 0 | 0 (0–1.92) | 225.8 |
| Estonia | 130 | 96.2 | 50, 19–71 | 27/02/2020 | 10–12/06/20 | 23 | 0 | 0 | 17.7 | 96 days | 0 | 0 (0–2.87) | 148.2 |
| Greece | 77 | 77.6 | 45, 18–67 | 26/02/2020 | 19/06–16/07/20 | 0 | 0 | 0 | 0.0 | 0 | 1 | 1.3 (0.23–7.0) | 34.5 |
| Latvia | 177 | 92.7 | 42, 20–73 | 03/03/2020 | 19/05–20/06/20 | 39 | 0 | 0 | 22.0 | 82 days | 0 | 0 (0–2.14) | 54.7 |
| Lithuania | 300 | 93.0 | 49, 22–70 | 28/02/2020 | 01–12/06/20 | 28 | 2 | 0.67 | 9.3 | 93 days | 2 | 0.66 (0.18–2.4) | 59.1 |
| Romania | 124 | 94.4 | 43, 21–65 | 26/02/2020 | 14/05/20–27/05/20 | 1 | 1 | 0.81 | 0.8 | Not available | 1 | 0.81 (0.14–4.3) | 87.6 |
| South Africa | 222 | 78.8 | 41, 19–67 | 05/03/2020 | 10/06–17/08/20 | 69 | 17 | 7.66 | 31.1 | 46 days | 23 | 10.36 (7–15.07) | 974.4 |
| UK | 1754 | 65.5 | 38, 19–69 | 15/02/2020 | 01/05–31/05/2020 | 772 | 15 | 0.86 | 44.0 | 64 days | 269 | 15.34 (13.73–17.1) | 390.1 |
| UK | 1134 | 72.9 | 37, 19–78 | 15/02/2020 | 01/06–30/06/2020 | 869 | 15 | 1.32 | 76.6 | 89 days | 192 | 16.93 (14.86–19.22) | 459.1 |
PCR, polymerase chain reaction; COVID-19, coronavirus disease 2019; CI, confidence interval.