Effectiveness of Flu Vaccination and Burden of Illness Among Community-dwelling Elderly With Influenza Like Illness in Brazil

An Observational Case Control Study of Effectiveness of Influenza Vaccination and Burden of Illness in Community-dwelling Elderly With Influenza-like Illness in Southern Brazil

The purpose of this research study is to estimate how many elderly people who have symptoms that look like influenza (i.e. an influenza-like illness) actually have the disease and how effective influenza vaccines are in preventing influenza in elderly people. The study will also examine the severity of the disease (e.g. how long are people ill, were there any complications) and how it affects everyday life (e.g. cost, medications, care by family members).

Inclusion Criteria:

• Subjects who the investigator believes that they can and will comply with the requirements of the protocol.

• A male or female >= 65 years of age.

• Written informed consent obtained from the subject.

• Presenting within the first 72 hours of an influenza-like illness. Influenza-like illness is defined as the presence of:

  • Fever measured by the patient or physician and at least one of the following symptoms:
  • Sore throat.
  • Coryza (runny nose) and/or nasal congestion.
  • Cough.

• Availability to be followed up by phone or in person after an interval of approximately 14 - 21 days.

Exclusion Criteria:

• Receipt of any experimental influenza vaccine within 6 months of the onset of the influenza-like illness.
• Terminal stage of disease.
• Subjects living in a nursing home.
• Use of any investigational or non-registered product planned during the study period.
• Subjects who have already been enrolled in this study.