Fluad vs. Fluzone High-Dose Vaccine Effectiveness Among Adults ≥65 Years
Relative Vaccine Effectiveness of Adjuvanted Quadrivalent Inactivated Influenza Vaccine vs High-Dose Quadrivalent Inactivated Influenza Vaccine Among Adults ≥65 Years for the 2023-24 and 2024-25 Seasons
1 other identifier
observational
960,000
1 country
1
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.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P75+ for all trials
Started Aug 2023
Typical duration for all trials
1 active site
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
Study Start
First participant enrolled
August 17, 2023
CompletedFirst Submitted
Initial submission to the registry
August 28, 2023
CompletedFirst Posted
Study publicly available on registry
September 8, 2023
CompletedPrimary Completion
Last participant's last visit for primary outcome
May 1, 2025
CompletedStudy Completion
Last participant's last visit for all outcomes
May 1, 2026
CompletedSeptember 8, 2023
September 1, 2023
1.7 years
August 28, 2023
September 1, 2023
Conditions
Outcome Measures
Primary Outcomes (1)
PCR-confirmed influenza
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).
≥14 days after vaccination until date of outcome, death, loss-to-follow-up, or end of each season (estimated May 2024 or May 2025)
Secondary Outcomes (3)
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)
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)
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)
Other Outcomes (2)
Hospitalization for cardiovascular events
≥14 days after vaccination until date of outcome, death, loss-to-follow-up, or end of each season (estimated May 2024 or May 2025)
PCR-confirmed influenza in subgroups with comorbidities
≥14 days after vaccination until date of outcome, death, loss-to-follow-up, or end of each season (estimated May 2024 or May 2025)
Study Arms (2)
Fluad Recipients
Kaiser Permanente Northern California members aged ≥65 years who receive Adjuvanted Quadrivalent Inactivated Influenza Vaccine (aIIV4)
Fluzone High-Dose Recipients
Kaiser Permanente Northern California members aged ≥65 years who receive High-Dose Quadrivalent Inactivated Influenza Vaccine (HD-IIV4)
Interventions
Fluad Quadrivalent vaccine is an inactivated influenza vaccine formulated to contain 60 mcg of hemagglutinin (HA) total, with 15 mcg from each of the four recommended influenza strains and the MF59 adjuvant in single-dose prefilled 0.5 mL syringes. Kaiser Permanente Northern California members ≥65 years may receive Fluad as part of routine clinical care during the influenza season.
Fluzone High-Dose Quadrivalent vaccine is an inactivated split virion influenza vaccine formulated to contain 240 mcg of HA total, with 60 mcg from each of the four recommended influenza strains in single-dose prefilled 0.7 mL syringes. Kaiser Permanente Northern California members ≥65 years may receive Fluzone High-Dose as part of routine clinical care during the influenza season.
Eligibility Criteria
This study includes KPNC adults ≥65 years who receive Fluad or Fluzone High-Dose influenza vaccine as part of routine clinical care during the 2023/24 and/or 2024/25 influenza seasons.
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
Contact the study team to confirm eligibility.
Sponsors & Collaborators
- Kaiser Permanentelead
- Seqiruscollaborator
Study Sites (1)
Kaiser Permanente Northern California (entire region)
Oakland, California, 94612, United States
MeSH Terms
Conditions
Interventions
Condition Hierarchy (Ancestors)
Intervention Hierarchy (Ancestors)
Central Study Contacts
Study Design
- Study Type
- observational
- Observational Model
- COHORT
- Time Perspective
- RETROSPECTIVE
- Sponsor Type
- OTHER
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
August 28, 2023
First Posted
September 8, 2023
Study Start
August 17, 2023
Primary Completion
May 1, 2025
Study Completion
May 1, 2026
Last Updated
September 8, 2023
Record last verified: 2023-09