Sentence: A re cent study of the med i cal care use re lat ed to in flu en za in the Unit ed King dom dur ing the mid-1990s found that in ab so lute terms adults aged 15-64 years had more in flu en za-re lat ed phy si cian visits and clin i cal com pli ca tions and greater drug use than chil dren or the el der ly ( 1 ). 
 Section: background