Table 1.

Comparison of the mean of IgG levels at different time period

Variable	First	Month 3	Month 6	F (df)	P value
IgG level (mean ± SD)	14.45 ± 5.88	7.49 ± 4.88	2.52 ± 2.33	544.59(2.96)	0.0001
Age (year)				2.208(1)	0.141
< 60	14.01 ± 5.29	7.32 ± 4.91	2.52 ± 2.39
≥ 60	16.97 ± 6.90	10.21 ± 4.06	3.53 ± 1.80