Table 1. Patient characteristics.

	Study participants	Healthy controls
	N = 39	N = 19
Demographics
Age	61.0 (52.5; 73.5)	53.0 (43.0; 63.0)
Gender (female)	29 (70.7%)	15 (79.0%)
Median time from 2. vaccine to sampling (days)	45.0 (33.0; 65.0)	70.5 (46.8; 85.8)
Clinical
CVID (n)	26 (66.7%)	n/a
IgG deficiency (n)	2 (5.1%)	n/a
Secondary immunodeficiency (drugs, neoplastic disease) (n)	2 (5.1%)	n/a
IgG subclass deficiency (n)	9 (23.1%)	n/a
Immunosuppressive drugs (n)	9 (23.1%)	n/a
IVIG (n)	36 (92.3%)	n/a
SCIG (n)	3 (8.3%)	n/a
Monthly dose (g)	25.0 (20.0; 30.0)	n/a
Laboratory
IgA (g/l)	0.58 (0.3; 1.2)	n/a
Baseline IgG before IVIG (g/l)	5.1 (3.6; 6.3)	n/a
IgG nadir value under IVIG/SCIG (g/l)	8.9 (8.1; 10.2)	n/a
SARS-CoV-2-IgG spike protein (AU/ml)	78.9 (12.0; 276.0)	250.0 (209.0; 358.0)

Values are median and interquartile ranges (IQR) for continuous variables. Categorical variables reported as n (%). Laboratory reference values: IgG 7.0–16.0 g/l, IgA 0.7–4.0 g/l, SARS-CoV-2-IgG spike protein cutoff 12 AU/ml.

Common variable immunodeficiency disease (CVID), intravenous immunoglobulin substitution (IVIG), subcutaneous immunoglobulin substitution (SCIG).