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Table 1 Seroprevalence of severe acute respiratory syndrome coronavirus 2-specifc IgG and IgM antibodies

From: Seroprevalence of SARS-CoV-2 antibody among urban Iranian population: findings from the second large population-based cross-sectional study

  Sample size, N Seropositive participants, n Seroprevalence  
Crude
(95% CI)
Weighted
(95% CI) a
Adjusted for test Scenario I
(95% CI)b
Adjusted for test Scenario II
(95% CI)c
P_value
Total 7411 1764 23.8 (22.8-24.8) 24.0 (21.8-26.2) 34.2 (31.0-37.3) 31.8 (28.8-34.7)  
Sex
Male 3721 876 23.5 (22.2-25.0) 23.7 (20.4-26.9) 33.6 (28.4-38.8) 31.2 (26.7-35.7) 0.597
Female 3690 888 24.1 (22.7-25.5) 24.3 (21.5-27.1) 34.7 (30.5-38.9) 32.3 (28.4-36.1)
Age, years
10-19 362 85 23.5 (19.2-28.2) 20.9 (14.7-27.2) 29.7 (20.1-39.4) 27.7 (18.7-36.6) < 0.0001
20-29 879 183 20.8 (18.2-23.7) 20.9 (17.2-24.7) 29.4 (23.9-35.0) 27.4 (21.7-33.1)
30-39 2202 480 21.8 (20.1-23.6) 23.1 (19.2-26.9) 32.6 (26.5-38.8) 30.4 (24.6-36.1)
40-49 2051 492 24.0 (22.1-25.9) 23.4 (19.9-26.8) 33.2 (27.9-38.4) 30.8 (26.0-35.7)
50-59 1272 331 26.0 (23.6-28.5) 25.0 (21.1-29.0) 35.7 (29.4-42.0) 33.2 (27.4-39.0)
≥ 60 645 193 29.9 (26.4-33.6) 34.4 (28.1-40.6) 50.2 (40.7-59.7) 46.7 (38.5-54.9)
Comorbidity
Yes 2229 561 25.2 (23.4-27.0) 23.7 (21.5-25.8) 32.4 (25.4-39.4) 30.1 (23.8-36.5) 0.062
No 5123 1186 23.1 (22.0-24.3) 22.9 (18.3-27.5) 33.6 (30.3-37.0) 31.3 (28.1-34.4)
Contact with confirmed COVID-19 patients
Yes 2557 730 28.5 (26.8-30.3) 29.5 (23.1-35.9) 42.6 (32.8-52.4) 37.0 (28.5-45.4) < 0.0001
No 4739 1010 21.3 (20.1-22.5) 21.3 (19.6-23.1) 30.0 (27.3-32.8) 26.1 (23.7-28.4)
Symptoms
 Asymptomatic (0) 4409 888 20.1 (19.0-21.3) 20.86 (18.86-22.85) 29.0 (26.2-31.9) 27.0 (24.6-29.5) < 0.0001
 Paucisymptomatic (1-3) 1797 398 22.1 (20.2-24.1) 21.77 (17.10-26.44) 32.9 (26.2-39.7) 30.6 (24.6-36.7)
 Symptomatic (≥4) 1149 460 40.0 (37.2-42.9) 37.5 (28.68-46.32) 61.0 (47.2-74.7) 56.8 (44.2-69.3)
  1. Seroprevalence data are % (95% confidence interval). aWeighted for age, sex and city population. bWeighted prevalence adjusted for test performance I (sensitivity 66·9% and specificity 98.2%). cWeighted prevalence adjusted for test performance II as reported by manufacturer (sensitivity 71.8% and specificity 98.2%). When a variable was stratified it was removed from the weight