Table 4.
Prevalence of serum antibodies to SARS-CoV-2 by participants' reported period of symptoms (N = 1813)
| N | Seroprevalence % (95% CI) | P-valuea | Adjusted P-valueb | OR (95% CI)c | OR adjusted P-valuec | |
|---|---|---|---|---|---|---|
| Period of 1+ symptoms onset | ||||||
| No symptoms | 811 | 10.0 (8.3–12.0) | <0.001 | <0.001 | Ref. | |
| Feb: 1st | 150 | 14.2 (10.0–19.7) | 1.58 (0.99–2.51) | 0.055 | ||
| Feb: 2nd | 197 | 30.5 (25.1–36.6) | 4.01 (2.83–5.68) | <0.001 | ||
| March: 1st | 380 | 56.7 (52.3–61.0) | 12.18 (9.18–16.14) | <0.001 | ||
| March: 2nd | 198 | 44.2 (38.2–50.3) | 7.03 (5.10–9.69) | <0.001 | ||
| April onwards | 77 | 7.6 (3.8–14.5) | 0.77 (0.36–1.64) | 0.496 | ||
| Period of 2+ symptoms onset | ||||||
| At most 1 symptom | 1133 | 14.2 (12.4–16.1) | <0.001 | <0.001 | Ref. | |
| Feb: 1st | 103 | 14.5 (9.6–21.2) | 1.10 (0.66–1.83) | 0.711 | ||
| Feb: 2nd | 129 | 35.8 (28.9–43.5) | 3.55 (2.46–5.11) | <0.001 | ||
| March: 1st | 278 | 63.2 (58.1–68.0) | 10.81 (8.23–14.20) | <0.001 | ||
| March: 2nd | 137 | 50.3 (42.9–57.6) | 5.93 (4.29–8.20) | <0.001 | ||
| April onwards | 33 | 14.9 (7.1–28.7) | 1.02 (0.44–2.40) | 0.955 | ||
a
Survey design adjusted F statistics.
b
Survey design adjusted F statistics, multiply adjusted for sex, age, BMI, smoking habit, main activity and municipality.
c
Odd ratios (ORs), 95% confidence intervals (95% CIs) and related adjusted P-values are obtained by linearised standard errors and logit transformation.