Post-marketing Surveillance Study for the Safety of Efluelda Tetra Pre-filled Syringe.

Post-marketing Surveillance Study for the Safety of Efluelda Tetra Pre-filled Syringe, a High-dose Quadrivalent Influenza Vaccine Administered to Adults 65 Years or Older in the Republic of Korea.

To investigate the incidence of adverse events (AEs) and adverse drug reactions (ADRs) occurred following administration of Efluelda Tetra in adults aged 65 years or older under routine clinical practice, as per approved indications.

The study duration of each participation will be approximately 28 to 35 days. In the event that Visit 2 is not made, the study duration would be extended to 36 to 42 days.

Inclusion Criteria:

• Adults aged 65 years or older on the day of enrollment
• The informed consent form has been signed and dated
• Receipt of 1 dose of Efluelda Tetra on the day of enrollment according to the approved local product label

Exclusion Criteria:

• Previous history of enrollment in this study
• Participation at the time of study enrollment (or in the 4 weeks preceding the enrollment) or planned participation during the present study period in a clinical study investigating a vaccine, drug, medical device or medical procedure