TABLE 2.

Comparison of amino acid sequences for the HA1 subunit of H3N2 viruses collected from 2002 to 2005

Group	Strain	Substitution at the following amino acid residue in HA1a:
		21	25	50d	75	83	131	144	145	155	156	159	186	189	193	202	222	225	226	227	275
	A/Panama/2007/99b	S	L	R	H	E	A	N	N	H	Q	Y	S	S	S	V	W	G	V	S	G
I	A/Hanoi/197/02	P	—c	G	—	K	—	D	K	—	—	—	G	—	—	I	R	D	—	—	D
I	A/Hanoi/1872/02	P	—	G	—	K	T	—	K	—	—	—	G	—	—	I	R	D	—	—	—
II	A/Fujian/411/02	P	I	G	Q	K	T	—	K	T	H	—	G	—	—	I	R	D	—	—	—
II	A/Hanoi/695/03	P	I	G	Q	K	T	—	K	T	H	—	G	—	—	I	R	D	—	—	—
IIIa	A/Wellington/7/04	P	I	G	Q	K	T	—	K	T	H	F	G	N	—	I	R	D	—	P	—
IIIa	A/Tay Nguyen/TN152/03	P	I	G	Q	K	T	—	K	T	H	F	G	N	—	I	R	D	—	P	—
IIIa	A/Hanoi/HN3069/04	P	I	G	Q	K	T	—	K	T	H	F	G	N	—	I	R	D	—	P	—
IIIa	A/Hanoi/HN3068/04	P	I	G	Q	K	T	—	K	T	H	F	G	N	—	I	R	D	I	P	—
IIIb	A/Califonia/7/04	P	I	G	Q	K	T	—	—	T	H	F	G	N	—	I	R	D	I	P	—
IIIb	A/Hanoi/ISBM69/05	P	I	G	Q	K	T	—	—	T	H	F	G	N	—	T	R	D	I	P	—
IV	A/Wisconsin/67/05	P	I	G	Q	K	T	—	—	T	H	F	G	N	F	I	R	N	I	P	—
IV	A/Hanoi/TN405/05	P	I	G	Q	K	T	—	—	T	H	F	G	N	F	I	R	N	I	P	—
IV	A/Hanoi/ISBM63/05	P	I	G	Q	K	T	—	—	T	H	F	G	N	F	I	R	N	I	P	—

^aResults are reported as amino acid differences between the sequences of the isolates and the sequence of the A/Panama/2007/99 vaccine strain.

^bItalic type indicates the reference vaccine strain.

^c—, no change.

^dDifferences located in the proposed antigenic sites are underlined.