The persistence of anti-Spike antibodies following two SARS-CoV-2 vaccine doses in patients on immunosuppressive therapy compared to healthy controls—a prospective cohort study

Table 2 Serological response at first and second assessment following two-dose vaccination in patients and controls

	Controls		Patients
	First sera assessment	Second sera assessment	First sera assessment	Second sera assessment
Median anti-RBD level (IQR)	6187 (4105–7496)	1520 (979–3766)	2806 (1018–6068)	608 (58–1053)
Median change in anti-RBD level (IQR)^#	− 3332 (− 5096 to − 2206)		− 2039 (− 4304 to − 806)
Median percent change in anti-RBD level (IQR)^*	− 66 (− 79 to − 49)		− 83 (− 94 to − 66)
Mean (SD) number of days between first and second assessment^##	75 (16)		75 (17)
Anti-RBD <5, n (%)	0	0	17 (1.5)	56 (5)
Anti-RBD 5–19, n (%)	0	0	13 (1)	74 (6.5)
Anti-RBD 20–199, n (%)	0	6 (5)	62 (6)	319 (29)
Anti-RBD 200–1999, n (%)	10 (7.5)	70 (52)	366 (33)	511 (46)
Anti-RBD 2000–8999, n (%)	107 (80)	58 (43)	599 (54)	145 (13)
Anti-RBD ≥ 9000, n (%)	17 (12.5)	0	51 (4.5)	3 (0.5)

First sera assessment 6–48 days after second vaccine dose. Second sera assessment 49–123 days after second vaccine dose. Serological response is anti-SARS-CoV-2 IgG antibodies to the receptor binding domain (RBD) measured as BAU/ml binding antibody units/ml, IQR inter quartile range
^#Change in median anti-RBD level compared across groups by Mann-Whitney U test: p <0.001
^*Percent change in anti-RBD level compared between groups by Mann-Whitney U test: p <0.001
^##Mean number of days between first and second assessment compared between groups by Student’s t-test p=0.77

ISSN: 1741-7015