NCT06029933

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

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Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Trial has exceeded expected completion date
Enrollment
960,000

participants targeted

Target at P75+ for all trials

Timeline
Completed

Started Aug 2023

Typical duration for all trials

Geographic Reach
1 country

1 active site

Status
recruiting

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

Completed
11 days until next milestone

First Submitted

Initial submission to the registry

August 28, 2023

Completed
11 days until next milestone

First Posted

Study publicly available on registry

September 8, 2023

Completed
1.6 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

May 1, 2025

Completed
1 year until next milestone

Study Completion

Last participant's last visit for all outcomes

May 1, 2026

Completed
Last Updated

September 8, 2023

Status Verified

September 1, 2023

Enrollment Period

1.7 years

First QC Date

August 28, 2023

Last Update Submit

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)

Biological: 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)

Biological: 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.

Also known as: Fluad
Fluad Recipients

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.

Also known as: Fluzone High-Dose
Fluzone High-Dose Recipients

Eligibility Criteria

Age65 Years+
Sexall
Healthy VolunteersYes
Age GroupsOlder Adult (65+)
Sampling MethodNon-Probability Sample
Study Population

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

Study Sites (1)

Kaiser Permanente Northern California (entire region)

Oakland, California, 94612, United States

RECRUITING

MeSH Terms

Conditions

Influenza, HumanCommunity-Acquired Pneumonia

Interventions

fluad vaccineInfluenza VaccinesFluzone High-Dose

Condition Hierarchy (Ancestors)

Respiratory Tract InfectionsInfectionsOrthomyxoviridae InfectionsRNA Virus InfectionsVirus DiseasesRespiratory Tract DiseasesCommunity-Acquired InfectionsPneumonia

Intervention Hierarchy (Ancestors)

Viral VaccinesVaccinesBiological ProductsComplex Mixtures

Central Study Contacts

Amber H. Hyman, PhD, MPH

CONTACT

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

Locations