Table 3.

Multiple linear regression analysis of anti-SARS-CoV-2 RBD IgG antibody levels above positivity cutoff in SARS-CoV-2 sero-negative individuals (2013 and 2020) and SARS-CoV-2 sero-positive individuals, with adjustment for age, sex, and anti-HCoV IgG signals.

Variable	2013 (N = 329)		2020 (N = 83)		SARS-CoV-2 Sero-Positives (N = 27)
	Coefficient	P-value	Coefficient	P-value	Coefficient	P-value
(Intercept)	4.009	–	3.685	–	-7.787	–
Age	0.005	<0.001	0.001	0.461	-0.029	0.127
Sex (Male)	0.035	0.372	0.021	0.818	-0.606	0.380
log(HCoV-229E Spike)	0.116	<0.001	0.0215	<0.001	0.734	0.175
log(HCoV-HKU1 Spike)	0.087	<0.001	0.065	0.183	-0.251	0.648
log(HCoV-NL63 Spike)	0.022	0.379	0.047	0.449	-0.549	0.252
log(HCoV-OC43 Spike)	0.031	0.243	-0.036	0.629	1.604	0.023
Adjusted R-squared	0.233		0.195		0.335