Table 1 Relationship between IgG anti-RBD (receptor binding domain) and anti-N (nucleocapsid) MFI (median fluorescence intensity) levels among cord blood samples with detectable SARS-CoV-2 IgA and/or IgM

From: Cord blood IgA/M reveals in utero response to SARS-CoV-2 with fluctuations in relation to circulating variants

 

Overall total tested for IgM/A N = 1038

IgG anti-RBD MFI < 700

IgG anti-RBD MFI700

IgG anti-N MFI

Total tested for IgM/A N = 59

IgG anti-N MFI

Total tested for IgM/A N = 979

300–699 N = 18

700 N = 41

300–699 N = 182

700 N = 797

Number with detectable IgM/A

298

4

2

6

51

241

292

Proportion with detectable IgM/A [95% CI]

0.287 [0.260, 0.316]

0.222 [0.064, 0.476]

0.049 [0.006, 0.165]

0.102 [0.038, 0.208]

0.280 [0.216, 0.351]

0.302 [0.271, 0.335]

0.298 [0.270, 0.327]

Isotypes

 IgM+ n (%)

31 (10.4)

1 (25.0)

1 (50.0)

2 (33.3)

10 (19.6)

19 (7.9)

29 (9.9)

 IgM+ IgA+ n (%)

40 (13.4)

1 (25.0)

1 (50.0)

2 (33.3)

8 (15.7)

30 (12.4)

38 (13.0)

 IgA+ n (%)

224 (75.2)

2 (50.0)

0

2 (33.3)

33 (64.7)

189 (78.4)

222 (76.0)

 IgA+ IgM unk n (%)

3 (1.0)

0

0

0

0

3 (1.3)

3 (1.0)

P-value

0.0003c

  

0.0639a

  

0.5908b

  1. All p-values were obtained by two-sided fisher’s exact tests; 95% CIs were exact binomial CIs; IgM positive only denoted by ‘IgM+’; both IgA and IgM positive denoted by ‘IgA+ IgM+’; IgA positive only denoted by ‘IgA+’; IgM positivity unknown denoted by ‘IgM unk’.
  2. Only samples with IgG anti-N 300 were tested for IgA and IgM.
  3. aThe difference in proportions with detectable IgM/A across N-levels among RBD/S <700.
  4. bTesting the difference in proportions with detectable IgM/A across N-levels among RBD700.
  5. cThe difference in proportions with detectable IgM/A between RBD <700 vs. RBD700.