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

Recruiting

• Conditions: Influenza; Community-acquired Pneumonia; Cardiovascular Events
• Interventions: Biological: Adjuvanted Quadrivalent Inactivated Influenza Vaccine (aIIV4); Biological: High-Dose Quadrivalent Inactivated Influenza Vaccine (HD-IIV4)

• Registration Number: NCT06029933
• Lead Sponsor: Kaiser Permanente

Brief Summary

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 and 2024/25 influenza seasons. The study is an observational study conducted at Kaiser Permanente Northern California (KPNC), an integrated health care system in the United States.

Detailed Description

Not available

Study Timeline

• Study Start: 2023-08-17
• Study First Submitted: 2023-08-28
• Status Verified: 2023-09
• Study First Submitted QC: 2023-09-01
• Last Update Submitted: 2023-09-01
• Study First Posted: 2023-09-08
• Last Update Posted: 2023-09-08
• Primary Completion: 2025-05
• Study Completion: 2026-05

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 960000

Inclusion Criteria

• 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

Exclusion Criteria

• 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

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Fluad Recipients	Adjuvanted Quadrivalent Inactivated Influenza Vaccine (aIIV4)	Kaiser Permanente Northern California members aged ≥65 years who receive Adjuvanted Quadrivalent Inactivated Influenza Vaccine (aIIV4)
Fluzone High-Dose Recipients	High-Dose Quadrivalent Inactivated Influenza Vaccine (HD-IIV4)	Kaiser Permanente Northern California members aged ≥65 years who receive High-Dose Quadrivalent Inactivated Influenza Vaccine (HD-IIV4)

Primary Outcome Measures

Name	Time	Method
PCR-confirmed influenza	≥14 days after vaccination until date of outcome, death, loss-to-follow-up, or end of each season (estimated May 2024 or May 2025)	KPNC members ≥65 years who receive Fluad or Fluzone High-Dose will be retrospectively assessed for the presence of PCR-confirmed influenza. This outcome will be assessed in single-season analyses (2023/24 and 2024/25 separately) and a pooled 2-seasons analysis (2023/24 and 2024/25 combined).

Secondary Outcome Measures

Name	Time	Method
Emergency department visit or hospitalization for PCR-confirmed influenza	≥14 days after vaccination until date of outcome, death, loss-to-follow-up, or end of each season (estimated May 2024 or May 2025)	KPNC members ≥65 years who receive Fluad or Fluzone High-Dose will be retrospectively assessed for an emergency department visit or hospitalization for PCR-confirmed influenza. This outcome will be assessed in single-season analyses (2023/24 and 2024/25 separately) and a pooled 2-seasons analysis (2023/24 and 2024/25 combined).
Hospitalization for PCR-confirmed influenza	≥14 days after vaccination until date of outcome, death, loss-to-follow-up, or end of each season (estimated May 2024 or May 2025)	KPNC members ≥65 years who receive Fluad or Fluzone High-Dose will be retrospectively assessed for hospitalization for PCR-confirmed influenza. This outcome will be assessed in a pooled 2-seasons analysis (2023/24 and 2024/25 combined).
Hospitalization for all-cause community-acquired pneumonia	≥14 days after vaccination until date of outcome, death, loss-to-follow-up, or end of each season (estimated May 2024 or May 2025)	KPNC members ≥65 years who receive Fluad or Fluzone High-Dose will be retrospectively assessed for hospitalization for all-cause community-acquired pneumonia. This outcome will be assessed in single-season analyses (2023/24 and 2024/25 separately) and a pooled 2-seasons analysis (2023/24 and 2024/25 combined).

Trial Locations

Locations (1)

Kaiser Permanente Northern California (entire region); 🇺🇸 Oakland, California, United States