title: [Letter: Seroimmunity against influenza (Hamburg 1974/1975)].
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005860:Germany, West; D006801:Humans; D007251:Influenza, Human / Q000175:diagnosis / Q000453:epidemiology / Q000276:immunology*; D008875:Middle Aged; D012698:Serologic Tests
vernacular_title: Seroimmunität gegen Influenza (Hamburg 1974/1975)