Assertion: vaccine's virus | /r/HasSubevent | difference
Facets:
value: compared with influenza a(h1n1
type: OTHER
value: between circulating influenza viruses
type: OTHER
value: more frequently
type: DEGREE
Source sentences:
text: viruses have more frequently resulted in differences between the virus components of the flu vaccine and circulating influenza viruses (i.e., antigenic change) compared with influenza A(H1N1) and influenza B viruses.