title: Letter: Influenza vaccine and P.P.D. skin-test reactivity.
mesh_terms: D000368:Aged; D002986:Clinical Trials as Topic; D005260:Female; D006801:Humans; D006968:Hypersensitivity, Delayed; D007252:Influenza Vaccines / Q000494:pharmacology* / Q000627:therapeutic use; D007251:Influenza, Human / Q000628:therapy; D007978:Levamisole / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010919:Placebos; D012867:Skin / Q000276:immunology; D014374:Tuberculin Test
chemical_list: D007252:Influenza Vaccines; D010919:Placebos; D007978:Levamisole