Table 2. GMTs of H1N1, H3N2 and B antibodies before immunization in the study groups.

Age group	Subgroup	No. of subjects	Antibody GMT (H1N1)	P value	Antibody GMT (H3N2)	P value	Antibody GMT (B)	P value
3–10 y	T1	149	3.27 ± 4.47	1.294	4.33 ± 5.14	0.74	31.52 ± 4.13	0.676
	T2	146	2.97 ± 4.11		3.66 ± 4.80		36.94 ± 3.82
	T3	140	3.41 ± 4.21		3.88 ± 4.65		30.74 ± 4.62
	C	218	3.41 ± 4.34		4.29 ± 5.08		34.02 ± 3.91
11–17 y	T1	166	3.21 ± 4.13	0.276	3.09 ± 4.05	0.352	54.36 ± 4.04	0.837
	T2	166	3.89 ± 4.29		3.48 ± 4.18		51.63 ± 3.92
	T3	159	2.86 ± 3.92		3.27 ± 4.06		47.52 ± 3.72
	C	251	3.37 ± 4.17		3.93 ± 4.21		51.21 ± 3.51
18–54 y	T1	155	1.76 ± 3.22	0.334	1.64 ± 2.81	0.771	51.34 ± 4.98	0.892
	T2	156	1.75 ± 3.22		1.57 ± 2.75		58.40 ± 4.94
	T3	151	1.83 ± 3.25		1.51 ± 2.62		55.53 ± 4.27
	C	229	1.52 ± 2.63		1.48 ± 2.51		56.60 ± 4.32
≥55 y	T1	152	2.18 ± 3.71	0.455	3.09 ± 3.60	0.353	78.56 ± 2.13	0.709

GMT, geometric mean titer; H1N1, H3N2, B, three strains of influenza.