title: A simple method for testing antigenic variation of influenza virus antigenicity.
mesh_terms: D000956:Antigens, Viral / Q000276:immunology*; D006385:Hemagglutination Inhibition Tests / Q000379:methods*; D006801:Humans; D007223:Infant; D009980:Influenza A virus / Q000276:immunology*
chemical_list: D000956:Antigens, Viral