Table 1.

Effect of second and third (booster) vaccinations on SARS-CoV-2 IgG antibody levels and neutralizing capacity in categories in 153 patients on chronic hemodialysis.

	Categories	Post Second Vaccination (No, %)		Post Third Vaccination (No, %)		Somers‘d
IgG	>433	84	54.9%	127	83.0%	<0.001
	216–433	10	6.5%	10	6.5%
	<216	59	38.6%	16	10.5%
% inhibition	>66	99	64.7%	136	88.9%	0.003
	33–66	23	15.0%	7	4.6%
	<33	31	20.3%	10	6.5%

Data are shown in numbers and % after the second and third vaccination. The variables were categorized into three parts each. SARS-CoV-2 IgG antibody titers are shown in BAU/mL, whereas the neutralizing capacity of the IgG antibodies is shown in % inhibition. Mean time between the two laboratory measurements was 158 ± 59 days. Somers’s test was applied to compare ordinal categories before and after the boost vaccination. A p-level of <0.05 was considered statistically significant. A paired t-test was applied to compare the neutralizing capacity of SARS-CoV-2 IgG antibodies (%) before (68 ± 33) and after (89 ± 24) the boost vaccination (p < 0.001).