Table 1.

IARC criteria for oncogenicity for six oncoviruses with HHV-6 comparison

Criteria	Characteristics	EBV	HTLV-1	HHV-8	HPV	HBV	HCV	HHV-6
Major criteria	Viral detection (diffuse)	X	X	X	X	X
	Tumor prevention (by antiviral vaccine)				a+/−	X
Minor criteria	Serology	X	X	X	X	X	X
	Viral detection (restricted)	N/A	N/A	N/A	N/A	N/A		X
	Biological gradients	X	X	X		X	X
	Clustering		X	X		X	X	b+/−
	Medical interventions				X	X	X	X
	Animal models	X	X			X

^aVaccine reduces number of precancerous lesions [51]

^bSome evidence supports clustering of HHV-6 [70, 71]