Table I.

Questionnaire sent to subjects participating in studies with vitamin D supplementation versus placebo.

To be answered by all: Did you have influenza this fall/winter? (Answer ‘yes’ if diagnosed by a doctor or if you had serious symptoms that you considered caused by the flu)

Did you receive an influenza vaccine this fall/winter? If so, was the vaccine against common influenza or H1N1 (‘Swine flu’) When did you receive the vaccine(s)?

To be answered only by those who had influenza this fall/winter: If you had influenza this fall/winter approximately when was it? How many days were you ill? When you had the influenza, did you have fever, cough, sore throat, runny nose, limb or joint pain, headache, vomiting or diarrhoea?

Did you see a doctor because of the influenza? Was the diagnosis of influenza confirmed with laboratory tests? If so, was it found to be common influenza or H1N1 (‘Swine flu’)?

Were you treated with Tamiflu because of the influenza? Were you admitted to hospital because of the influenza? If so, how many days were you admitted?