Special Drug Use Investigation for Relenza® (Zanamivir) (Prophylaxis)

<Zanamivir prophylactic administration group> Subjects meeting all of the following criteria and starting prophylactic administration of zanamivir

• family or persons living with patients with influenza virus infection
• subjects meeting any of the following criteria, elderly subjects ( 65 years old and over), subjects with chronic cardiac disease, with metabolic disease (diabetes, etc.) or with renal dysfunction
• unvaccinated persons during the applicable seasons
• subjects whose consent to write influenza diary was obtained

<Non-zanamivir prophylactic administration group>

- subjects meeting all of the above criteria and NOT starting prophylactic administration of zanamivir

Inclusion Criteria:

• Subjects who meet the study population criteria

Exclusion Criteria:

• Subjects with a history of hypersensitivity to the ingredients of zanamivir