TABLE 2.

Characteristics of patients infected with the H275Y mutant influenza A(H1N1)pdm09 viruses

Patient characteristic	No. (%) with characteristic among:		P value
	Sapporo/Hokkaido cluster (n = 45)	Sporadic cases (n = 59)
Male sex	27 (60)	32 (54)	0.69
Age <10 yr	26 (58)	49 (83)	0.008
Hospitalized	1 (2)	12 (20)	0.006
No exposure to NA inhibitors	44 (98)	19 (32)	<0.0001