Repeated negative RT-PCR in the last 12 months (n=589) Repeated negative RT-PCR in the last 12 months (n=589) Positive RT-PCR (n=222) Positive RT-PCR (n=222)
P value
Negative N-Protein IgGa (n= 554) Positive N-Protein IgGb (n=35) 9 to 12 months agoc (n=72) 3 to 7 months agod (n=150)
Sex Female (%) Male (%) 387 (69.9) 167 (30.1) 32 (91.4) 3 (8.6) 52 (72.2) 20 (27.8) 121 (80.7) 29 (19.3)
<.01
Age, mean (SD), year 86.2 (9.0) 85.6 (7.2)) 87.4 (8.6) 88.0 (8.5) NS
SARS-CoV-2 S-protein IgG level
0-50 AU/mL 17 (3.1) 1 (2.9) 0 (0) 1 (0.7)
50-1050 AU/mL 146 (26.3) 2 (5.7) 0 (0) 5 (3.3)
1050-4160 AU/mL 231 (41.7) 5 (14.3) 6 (8.3) 12 (8.0)
≥ 4160 AU/mL 160 (28.9) 27 (77.1) 66 (91.7) 132 (88.0)
SARS-CoV-2 S-protein level median (Q1-Q3) [range], AU/mL
2384 (827; 4902)[0-40,000]
18239 (5876; 38418) [0; 40000][0-40,000]
39525 (19601; 4000) [6-14142]
28863 (12083; 40000)[1-40,000]
<.001 between a and b,c,d <.001 between c and b,d