title: Letter: Influenza virus subunit vaccine: a case for two doses.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000914:Antibodies, Viral / Q000096:biosynthesis*; D006801:Humans; D007115:Immunization Schedule; D007252:Influenza Vaccines / Q000008:administration & dosage*; D008875:Middle Aged; D009975:Orthomyxoviridae / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines