Influenza-like illness in Norway: clinical course, attitudes towards vaccination and preventive measures during the 2009 pandemic.

Objectives. To document clinical characteristics of influenza-like illness, reported use of health preventive measures and attitudes towards vaccination among patients with influenza-like illness in general practice during the influenza pandemic in 2009. Methods. Cross-sectional survey in general practice. Patients, who were identified as having influenza-like illness during the peak of the influenza pandemic activity in Norway, were eligible for inclusion in the study. A questionnaire was sent 2-4 weeks after the patients visit to the GP with influenza-like illness diagnosis during October to December 2009, from general practices in Norway. A sample of responders > 18 years also had a blood test to check for serological response to the pandemic H1N1 virus. Results. Questionnaires were sent to 1324 patients, and 357 (27%) were returned. Fever (91% versus 49%, P < 0.01), cough (85% versus 73%, P = 0.016) and gastrointestinal symptoms (58% versus 38%, P < 0.01) were more frequent in the age group < 18 years compared to older patients. Serological H1N1 responses were analysed in 72 patients; 34 (47%) were positive (haemagglutination inhibition assay titres >= 40). There were no statistically significant differences in symptoms between seropositive and seronegative patients. Women reported better adherence to personal protective measures, such as hand washing and cough etiquette than men. Women were also more concerned about possible adverse effects of the pandemic influenza vaccine than men. Conclusions. Discrimination between influenza and other viral upper respiratory tract infections is difficult in daily clinical practice, even during an influenza pandemic. A gender difference was found in reported precautions to prevent influenza.