Table 3.

Linear regression models of SARS-CoV-2 IgG antibody titer

		Vaccinated			Convalescent
		factor	95% CI	P	factor	95% CI	P
(Intercept)		10,598	[4,889–22,975]	<0.001	234	[143–384]	<0.001
Each month since vaccination		0.623	[0.599–0.649]	<0.001
Each month since first positive (for convalescent)					0.960	[0.939–0.982]	<0.001
was symptomatic (for convalescent)					1.811	[1.531–2.142]	<0.001
was hospitalized (for convalescent)					3.323	[2.217–4.980]	<0.001
Age	≥ 60 (vs. < 60)	0.790	[0.644–0.969]	0.024	1.546	[1.269–1.884]	<0.001
Sex	Female (vs. Male)	1.243	[1.035–1.492]	0.020	0.923	[0.812–1.048]	0.215
Socio-economic status (SES)		0.995	[0.966–1.024]	0.723	0.995	[0.973–1.018]	0.662
Ethnicity (vs. general)	Arab	1.525	[1.101–2.113]	0.011	0.982	[0.789–1.222]	0.871
	Ultra-orthodox	1.436	[1.099–1.877]	0.008	1.261	[1.065–1.492]	0.007
Body Mass Index (BMI)	<18.5 Underweight	0.359	[0.144–0.893]	0.028	0.683	[0.404–1.157]	0.156
	18.5–25 Normal	0.757	[0.374–1.534]	0.440	0.880	[0.581–1.333]	0.547
	25–30 Overweight	0.774	[0.383–1.564]	0.475	1.143	[0.754–1.733]	0.529
	30–35 Obese	0.804	[0.393–1.645]	0.550	1.429	[0.930–2.194]	0.103
	≥ 35 Obese II+	0.647	[0.307–1.363]	0.252	1.839	[1.166–2.899]	0.009
Co-morbidities	diabetes mellitus	0.720	[0.579–0.894]	0.003	1.354	[1.093–1.678]	0.006
	hypertension	0.786	[0.639–0.966]	0.022	1.254	[1.036–1.518]	0.020
	asthma	1.200	[0.911–1.582]	0.195	1.046	[0.848–1.290]	0.676
	COPD	0.643	[0.479–0.863]	0.003	0.798	[0.562–1.133]	0.207
	ischemic heart disease	0.869	[0.655–1.152]	0.328	1.322	[0.956–1.828]	0.091
	solid tumor	0.642	[0.494–0.834]	0.001	1.048	[0.760–1.444]	0.777
	chronic renal disease	0.200	[0.143–0.281]	<0.001	1.965	[1.134–3.407]	0.016

Regression coefficients were obtained by fitting a linear regression model for the log of antibody titer. They are displayed after exponentiation, they are therefore multiplicative: the expected antibody titer equals the intercept multiplied by each factor