Table 3. Frequency of amino acid mutations in the hemagglutinin receptor binding site in egg-passaged or MDCK-passaged samples.

Specimen	Isolation	Total Read	Mutant Ratio (%)
			K119N	N125D	D187E	D222G	Q223R
#1	P1	495	0.6	0.2	0	3	95.6
	P6	330	0	96.7	12.1	7.9	95.8
	MDCK	481	0.2	0.8	1.5	1.9	2.7
#2	P1	340	0.6	12.1	0.3	24.4	70.6
	P6	202	60.4	33.7	25.7	60.4	33.2
	MDCK	515	0	0	0	0.4	0
#3	P1	300	0.7	0	0	59	0.7
	P5	193	49.2	36.3	0	85	0.5