Table 3.

Anti-SARS-CoV-2 activity and fold changes of IgG fractions eluted from day-60 sera against VOCs and VUM compared to those against wild-type Wuhan strain.

Strains	Wuhan	Alpha			Beta	Gamma	Delta	Kappa	E484K
	05-2N	QHN001	QK002	QHN002	TY8-612	TY7-501	K1734	K5356	F-76107	F-76137
(A) High responder’s sera (n = 15)
Average EC50 (μg/ml)	10.8 ± 5.6	25.6 ± 10.0	24.5 ± 4.0	26.3 ± 8.3	77.3 ± 22.2	34.2 ± 10.7	25.7 ± 4.6	25.7 ± 6.8	25.3 ± 8.3	30.1 ± 7.0
Fold changes*	–	2.4	2.3	2.4	7.2	3.2	2.4	2.4	2.3	2.8
p value vs 05-2N	–	< 0.001	< 0.001	< 0.001	< 0.001	< 0.001	< 0.001	< 0.001	< 0.001	< 0.001
(B) Moderate responder’s sera (n = 30)
Average EC50 (μg/ml)	23.8 ± 8.8	50.1 ± 18.2	64.0 ± 24.0	60.5 ± 22.2	144.5 ± 35.9	102.1 ± 32.7	49.0 ± 17.9	81.3 ± 16.8	54.1 ± 21.1	61.0 ± 23.6
Fold changes*	–	2.1	2.7	2.5	6.1	4.3	2.1	3.4	2.3	2.6
p value vs 05-2N	–	< 0.001	< 0.001	< 0.001	< 0.001	< 0.001	< 0.001	< 0.001	< 0.001	< 0.001

Average EC₅₀ values of IgG fraction eluted from day-60 sera of high (n = 15) or moderate (n = 30) responders against SARS-CoV-2^05-2N and various variants are indicated.

*Fold change of EC₅₀ values compared to that against SARS-CoV-2^05-2N.