title: Influenza immunization status and viral respiratory tract infections in patients with chronic airflow limitation.
mesh_terms: D000368:Aged; D003168:Complement Fixation Tests; D004739:England; D005260:Female; D006801:Humans; D007251:Influenza, Human / Q000517:prevention & control*; D008173:Lung Diseases, Obstructive / Q000150:complications*; D008297:Male; D008875:Middle Aged; D012141:Respiratory Tract Infections / Q000150:complications* / Q000453:epidemiology; D016312:Treatment Refusal; D014611:Vaccination / Q000706:statistics & numerical data*; D014777:Virus Diseases / Q000150:complications* / Q000453:epidemiology