Table 5.

Factors associated with antibody responses in Delta- and omicron-infected groups of participants at Hospital A

Ab rising ≥ 2-fold compared to day 0	Factors	Percentagea	χ2 p-value	Odds ratio	95% CI	p-value
Delta-infected group
Delta IgG at day 14	Pneumonia	85.7%	0.007*	24.000	1.689–340.992	0.019*
	No pneumonia	20.0%
Delta IgG at year 1	Obesity	25.0%	0.014*	0.063	0.005–0.823	0.035*
	Normal BMI	84.2%
Delta IgA at day 28	Pneumonia	77.3%	0.021*	5.950	1.223–28.951	0.027*
	No pneumonia	36.4%
Omicron IgG at day 28	Obesity	75.0%	0.032*	6.375	1.046–38.858	0.045*
	Normal BMI	32.0%
Omicron IgA at day 14	Hypertension	88.9%	0.027*	12.000	1.053–136.794	0.045*
	No hypertension	40.0%
	Dyslipidemia	100.0%	0.047*	-	-	-
	No dyslipidemia	50.0%
Omicron-infected group
Delta IgG at day 14	Age ≥ 60	55.6%	0.028*	8.125	1.115–59.212	0.039*
	Age 18–59	13.3%
Omicron IgA at day 14	Hypertension	100.0%	0.028*	-	-	-
	No hypertension	60.0%
Omicron IgA at day 28	Diabetes	100.0%	0.028*	-	-	-
	No diabetes	58.3%

a, Percentage of participants presented with antibody rising ≥ 2-fold in each factor category; *, statistically significant at p ≤ 0.05