Table 3 Demographic, clinical and geometric mean antibody titers (GMAT) of anti-spike IgG antibodies among infected and non-infected subjects

All patients (n = 191)^a

145

46

Age, median (IQR)

84 (80–87)

85 (81–91)

0.38

Gender (female), n (%)

102 (70)

28 (61)

0.28

Residence

 Nursing home^b

 Assisted-living care homes

55 (61)

89 (89)

35 (38.9)

11 (11)

< 0.001

Diabetes

31 (21.4)

13 (28.3)

0.32

Hypertension

98 (67.6)

31 (67.4)

1

Obesity

6 (4.1)

5 (10.9)

0.14

Cancer

17 (11.7)

6 (13.3)

0.8

Lung disease

16 (11)

7 (15.2)

0.4

Ischemic heart disease

59 (40.7)

20 (43.5)

0.8

Number of comorbidities (mean ± SD)

2 ± 1.3

2.3 ± 1.3

0.1

Number of vaccines

1

2

3

2 (1.3)

14 (10)

129 (89)

0

7 (15.2)

38 (85)

1

0.3

0.4

Past infection (recovered)

22 (15)

7 (15)

1

2nd antibody titer level (Geometric mean, 95% CI, Au/ml)

4468 (3629–5503)

2030 (1323–3115)

< 0.001