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Table 2 Test results as a function of time following an initial positive result

From: Duration of SARS-CoV-2 sero-positivity in a large longitudinal sero-surveillance cohort: the COVID-19 Community Research Partnership

  Baseline* Month 1 Month 2 Month 3 Month 4 Month 5 Month 6  > 6 Months
  n n % n % n % n % n % n % n %
Seropositive cohort               
IgM                
 Negative 0 59 48.8% 257 61.8% 255 78.7% 227 88.0% 155 93.4% 168 92.3% 99 93.4%
 Positive 973 62 51.2% 159 38.2% 69 21.3% 31 12.0% 11 6.6% 14 7.7% 7 6.6%
IgG                
 Negative 0 23 41.1% 73 38.6% 57 57.6% 79 71.2% 34 75.6% 38 95.0% 17 70.8%
 Positive 532 33 58.9% 116 61.4% 42 42.4% 32 28.8% 11 24.4% 2 5.0% 7 29.2%
IgG or IgM                
 Negative 0 63 42.6% 255 52.4% 264 73.3% 254 83.6% 163 88.6% 181 92.3% 107 89.9%
 Positive 1172 85 57.4% 232 47.6% 96 26.7% 50 16.4% 21 11.4% 15 7.7% 12 10.1%
IgG and IgM                
 Negative 0 19 65.5% 74 64.4% 44 71.0% 52 81.3% 23 85.2% 25 96.2% 8 72.7%
 Positive 330 10 34.5% 41 35.7% 18 29.0% 12 18.8% 4 14.8% 1 3.9% 3 27.3%
Subset with initial positive IgG and IgM            
IgG and IgM                
 Negative 0 19 65.5% 74 64.4% 44 71.0% 52 81.3% 23 85.2% 25 96.2% 8 72.7%
 Positive 330 10 34.5% 41 35.7% 18 29.0% 12 18.8% 4 14.8% 1 3.9% 3 27.3%
IgG or IgM                
 Negative 0 13 44.8% 44 38.3% 33 53.2% 38 59.4% 17 63.0% 22 84.6% 6 54.6%
 Positive 330 16 55.2% 71 61.7% 29 46.8% 26 40.6% 10 37.0% 4 15.4% 5 45.5%
Subset with negative test ≤ 60 days prior            
IgG or IgM                
 Negative 0 38 52.1% 90 65.7% 58 69.1% 48 72.7% 47 79.7% 36 85.7% 31 83.8%
 Positive 371 35 48.0% 47 34.3% 26 31.0% 18 27.3% 12 20.3% 6 14.3% 6 16.2%
  1. *Defined as the first positive test