Influenza ProtectionProtection From Influenza: Determining the Impact of Prior Infection

Inclusion Criteria:

1. Written informed consent provided by the participant.
2. Age 65 years of age or older admitted to Health Sciences North with at least one the following:

• Laboratory confirmed influenza illness
• Acute exacerbation of chronic obstructive pulmonary disease (AECOPD).
• Any respiratory or influenza-like symptoms (dyspnea, cough, sore throat, myalgia, arthralgia, fever, delirium/altered level of consciousness) that a test for influenza was negative.

3. Willing to receive influenza vaccination in the subsequent flu season

Exclusion Criteria:

1. Patients whose reason for hospital admission was unrelated to influenza or (for example patients admitted due to trauma, elective surgery, or patients who have an alternative diagnosis that is clearly not respiratory).
2. Chest x-ray positive for pneumonia.
3. Study participants who cannot be vaccinated due to previous severe reaction to influenza vaccine, egg, latex, or thimerosol allergies, or refusal of vaccination.
4. Immunosuppressive disorders or medications (including oral prednisone in doses >10 mg daily).