TABLE 4.

Univariate and multivariate regression analysis of IgA antibody levels in 451 Omicron breakthrough cases^a,b

Variable	No. observed	Univariate regression		Multivariate regressiona,b
		Bc	P	B	P
Total	451
Gender
Male	271	Referenced		Reference
Female	180	−1.833	0.110	−2.087	0.057
Age (yrs)
<18	52	−1.395	0.433	−1.825	0.285
18−65	341	Reference		Reference
>65	58	−0.709	0.676	−1.908	0.240
Booster dose
Yes	204	0.556	0.622
No	247	Reference
Wks since onset
0	32	−1.275	0.551	−1.364	0.523
1	217	Reference		Reference
2	137	5.931	<0.001	6.016	<0.001
3	33	8.819	<0.001	9.646	<0.001
4	17	10.174	<0.001	9.927	0.001
5	15	13.066	<0.001	13.365	<0.001

^aDependent variable: IgA.

^bR = 0.354, R square = 0.125, adjusted R square = 0.109, F = 7.912, P < 0.001.

^cRepresents partial regression coefficient.

^dRefers to the reference group of a variable in the model. Bold text indicates that the differences observed are statistically significant.