Fluad vs. Fluzone High-Dose Vaccine Effectiveness Among Adults ≥65 Years

Recruiting now

Conditions studied: Influenza, Community-acquired Pneumonia, Cardiovascular Events

In brief

This study will evaluate the relative vaccine effectiveness of quadrivalent adjuvanted inactivated influenza vaccine (aIIV4) versus quadrivalent high-dose inactivated influenza vaccine (HD-IIV4) in preventing polymerase chain reaction (PCR)-confirmed influenza and influenza-related outcomes in adults ≥65 years of age during the 2023/24, 2024/25, and 2026/27 influenza seasons. The study is an observational study conducted at Kaiser Permanente Northern California (KPNC), an integrated health care system in the United States.

Key facts

Study ID

NCT06029933

Run by

Kaiser Permanente

People needed

1500000

Starts

2023-08-17

Expected to finish

2028-05-01

Last updated by the study team

2026-08-05

Who can join

Age: 65 and older. Sex: any. Healthy volunteers: accepted.

You may qualify if…

• Age ≥65 years at the time of influenza vaccination
• KPNC member at the time of vaccination
• Receive either aIIV4 or HD-IIV4 at a KPNC facility during the 2023/24 and/or 2024/25 influenza seasons

You may not qualify if…

• Age <65 years at the time of influenza vaccination
• Received either aIIV4 or HD-IIV4 in the inpatient setting
• Receive more than one influenza vaccination during a single season period (i.e., 2023/24 or 2024/25 influenza seasons)
• Receive an influenza vaccination outside of KPNC

Where it is running

• Kaiser Permanente Northern California (entire region) — Oakland, California, United States (enrolling)

Full record on ClinicalTrials.gov

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