InfluenzaNCT03694392
Flublok v. Standard Dose Vaccine Effectiveness Among Kaiser Permanente Northern California Adults 18-64 Years
An observational study of Influenza and Pneumonia, run by Kaiser Permanente at 1 site in United States.
Trial summary
The overall objective of this study is to describe the effectiveness of Flublok Quadrivalent vaccine compared to standard dose inactivated influenza vaccine (SD-IIV) in adults 18 through 64 years of age. Read more about this study
- Who is it for?
- Ages 18 to 64 yearsHealthy volunteers can take part
- Conditions the study is for
- Influenza, Pneumonia, Lower Respiratory Tract Infection
- What is being tested?
- Flublok Quadrivalent and Standard Dose Inactivated Influenza Vaccine (SD-IIV)
- Type of treatment
- Vaccines
- How many people
- 2,776,278 participants
- Where
- 1 siteUnited States
- Study dates
- 16 Sep 2018to 31 Dec 2022
- Phase
- Observational
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 64 years
- All sexes
- Healthy volunteers accepted
- Adult
Study population: Eligible adults aged 18-64 years will receive either Flublok Quadrivalent vaccine or a standard dose inactivated influenza vaccine in the course of routine influenza vaccination during each of the two influenza seasons of the study period at Kaiser Permanente Northern California.
Who may be able to join
- Between the ages of ≥18 and <65 years at the time of influenza vaccination
- Receive either Flublok Quadrivalent vaccine or standard dose inactivated influenza vaccine at a Kaiser Permanente Northern California facility during the study period from August 2018 through April 2020
Who cannot join
- Children <18 years old
- Adults ≥65 years old
Trial locations and contacts
1 site in 1 country.
United States1 site
Kaiser Permanente Northern California (entire region)
Oakland, California, 94612
About this study
Official title: Examining Vaccine Effectiveness (VE) of Flublok Relative to Standard Dose Inactivated Influenza Vaccine Among Kaiser Permanente Northern California Members Aged 18-64 Years
The overall objective of this study is to describe the effectiveness of Flublok Quadrivalent vaccine compared to standard dose inactivated influenza vaccine (SD-IIV) in adults 18 through 64 years of age. During this study, Flublok Quadrivalent or SD-IIV will be administered according to the guidelines in the Prescribing Information materials and only to persons for whom it is indicated. The 2018-2019, 2019-2020, and 2020-2021 formulations of recombinant influenza vaccine (Flublok Quadrivalent vaccine) and SD-IIV will be evaluated for outcomes including all polymerase chain reaction (PCR)-confirmed influenza, PCR-confirmed hospitalized influenza, hospitalized community-acquired pneumonia and cardio-respiratory events.
- Conditions
- Influenza, Pneumonia, Lower Respiratory Tract Infection, Acute Myocardial Infarction, Congestive Heart Failure, Stroke
- Being tested
- Flublok Quadrivalent, Standard Dose Inactivated Influenza Vaccine (SD-IIV)
- Keywords
- influenza, vaccine effectiveness
- Medical subject headings
- Influenza, Human, Pneumonia, Heart Failure, Stroke
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Flublok QuadrivalentBiological
Flublok Quadrivalent vaccine is a recombinant hemagglutinin influenza vaccine indicated for active immunization against disease caused by influenza A subtype viruses and type B viruses contained in the vaccine for adults 18 years of age and older. Use of recombinant DNA techniques to produce vaccine antigen expressed in cell culture is a method that avoids growing the influenza viruses in embryonated hen's eggs.
Standard Dose Inactivated Influenza Vaccine (SD-IIV)Biological
For the 2018-2019, 2019-2020, and 2020-2021 flu seasons, the primary SD-IIVs used will be Fluarix Quadrivalent and Flulaval Quadrivalent.
| Study group | Role | What they receive |
|---|---|---|
| Flublok Recipients | Kaiser Permanente Northern California members aged 18-64 years who receive Flublok Quadrivalent vaccine. Receives: Biological: Flublok Quadrivalent | |
| SD-IIV Recipients | Kaiser Permanente Northern California members aged 18-64 years who receive standard dose inactivated influenza vaccine (SD-IIV). Receives: Biological: Standard Dose Inactivated Influenza Vaccine (SD-IIV) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Adults 50-64 Years Old With Polymerase-chain Reaction (PCR) Confirmed Influenza Tests
Patients who receive either Flublok or SD-IIV will be retroactively assessed for whether they had a PCR-confirmed positive influenza test (≥14 days after vaccination) as recorded in their electronic medical record by the end of the influenza season (April 30).
Measured: Up to 8 months
Secondary outcomes (5)
Number of Adults 50-64 Years Old Hospitalized With PCR-confirmed Influenza
Patients who receive either Flublok or SD-IIV will be retroactively assessed for whether they had an inpatient stay and had a PCR-confirmed positive influenza test (≥14 days after vaccination) as recorded in their electronic medical record by the end of the influenza season (April 30).
Measured: Up to 8 months
Number of Adults 50-64 Years Old Hospitalized With Community-acquired Pneumonia
Patients who receive either Flublok or SD-IIV will be retroactively assessed for whether they had an inpatient stay for community-acquired pneumonia (≥14 days after vaccination) as recorded in their electronic medical record by the end of the influenza season (April 30).
Measured: Up to 8 months
Number of Adults 50-64 Years Old Hospitalized With Cardio-respiratory Events
Patients who receive either Flublok or SD-IIV will be retroactively assessed for whether they had an inpatient stay for cardio-respiratory events (e.g., pneumonia, other lower respiratory infections, acute myocardial infarction, congestive heart failure, stroke) (≥14 days after vaccination) as recorded in their electronic medical record by the end of the influenza season (April 30).
Measured: Up to 8 months
Number of Adults 50-64 Years Old With Polymerase-chain Reaction (PCR) Confirmed Influenza A Tests
Patients who receive either Flublok or SD-IIV will be retroactively assessed for whether they had a PCR-confirmed positive influenza A test (≥14 days after vaccination) as recorded in their electronic medical record by the end of the influenza season (April 30).
Measured: Up to 8 months
Number of Adults 50-64 Years Old With Polymerase-chain Reaction (PCR) Confirmed Influenza B Tests
Patients who receive either Flublok or SD-IIV will be retroactively assessed for whether they had a PCR-confirmed positive influenza B test (≥14 days after vaccination) as recorded in their electronic medical record by the end of the influenza season (April 30).
Measured: Up to 8 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Oct 2018
- Study start16 Sep 2018
- Primary completion9 Apr 2021
- Study completion31 Dec 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for InfluenzaStudies of the same condition, open and under way.
- More trials run by Kaiser PermanenteThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 2,776,278 participants (actual)
Sponsor and investigators
- Lead sponsor
- Kaiser Permanente
- Sponsor type
- University, hospital or other
- Collaborators
- Sanofi Pasteur, a Sanofi Company
- Responsible party
- Sponsor
- Investigators
- Nicola P Klein, MD, PhD, Principal investigator, Kaiser Permanente
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03694392
- Sponsor's protocol ID
- CN-18-3176
- Status last verified
- Mar 2025
- First submitted
- 27 Sep 2018
- Last updated
- 8 Apr 2025
- Results posted
- Yes, on ClinicalTrials.gov
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No: All data reported to Sanofi Pasteur by the Kaiser Permanente Northern California Vaccine Study Center will be deidentified and aggregated.
Publications
Hsiao A, Yee A, Izikson R, Fireman B, Hansen J, Lewis N, Gandhi-Banga S, Selmani A, Talanova O, Kabler H, Inamdar A, Klein NP. Safety of quadrivalent recombinant influenza vaccine in pregnant persons and their infants. AJOG Glob Rep. 2024 Sep 20;4(4):100395. doi: 10.1016/j.xagr.2024.100395. eCollection 2024 Nov.
PubMed 39512761Hsiao A, Yee A, Fireman B, Hansen J, Lewis N, Klein NP. Recombinant or Standard-Dose Influenza Vaccine in Adults under 65 Years of Age. N Engl J Med. 2023 Dec 14;389(24):2245-2255. doi: 10.1056/NEJMoa2302099.
PubMed 38091531Hsiao A, Hansen J, Nunley KV, Lewis N, Selmani A, Inamdar A, Mallett-Moore T, Izikson R, Rudin D, Klein NP. Safety of recombinant quadrivalent influenza vaccine compared to inactivated influenza vaccine in Chinese adults: An observational study. Vaccine. 2022 Jan 31;40(5):774-779. doi: 10.1016/j.vaccine.2021.12.035. Epub 2022 Jan 6.
PubMed 34998605
Study at a glance
From the registry record, last updated by the sponsor on 8 Apr 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Examining Vaccine Effectiveness (VE) of Flublok Relative to Standard Dose Inactivated Influenza Vaccine Among Kaiser Permanente Northern California Members Aged 18-64 Years
- ClinicalTrials.gov ID
- NCT03694392
- Acronym / sponsor ID
- CN-18-3176
- Conditions
- Influenza, Pneumonia, Lower Respiratory Tract Infection, Acute Myocardial Infarction, Congestive Heart Failure, Stroke
- Keywords
- influenza, vaccine effectiveness
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 2,776,278 participants (actual)
- Lead sponsor
- Kaiser PermanenteUniversity, hospital or other
- Collaborators
- Sanofi Pasteur, a Sanofi Company
- Study start
- 16 Sep 2018 (actual)
- Primary completion
- 9 Apr 2021 (actual)
- Study completion
- 31 Dec 2022 (actual)
- First posted
- 3 Oct 2018 (actual)
- Results
- Posted 8 Apr 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The overall objective of this study is to describe the effectiveness of Flublok Quadrivalent vaccine compared to standard dose inactivated influenza vaccine (SD-IIV) in adults 18 through 64 years of age. During this study, Flublok Quadrivalent or SD-IIV will be administered according to the guidelines in the Prescribing Information materials and only to persons for whom it is indicated. The 2018-2019, 2019-2020, and 2020-2021 formulations of recombinant influenza vaccine (Flublok Quadrivalent vaccine) and SD-IIV will be evaluated for outcomes including all polymerase chain reaction (PCR)-confirmed influenza, PCR-confirmed hospitalized influenza, hospitalized community-acquired pneumonia and cardio-respiratory events.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Flublok Recipients | – | Biological: Flublok QuadrivalentKaiser Permanente Northern California members aged 18-64 years who receive Flublok Quadrivalent vaccine. |
| SD-IIV Recipients | – | Biological: Standard Dose Inactivated Influenza Vaccine (SD-IIV)Kaiser Permanente Northern California members aged 18-64 years who receive standard dose inactivated influenza vaccine (SD-IIV). |
Who may qualify
- Ages
- 18 to 64 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
- Study population
- Eligible adults aged 18-64 years will receive either Flublok Quadrivalent vaccine or a standard dose inactivated influenza vaccine in the course of routine influenza vaccination during each of the two influenza seasons of the study period at Kaiser Permanente Northern California.
Key inclusion criteria (2 listed)
- Between the ages of ≥18 and <65 years at the time of influenza vaccination
- Receive either Flublok Quadrivalent vaccine or standard dose inactivated influenza vaccine at a Kaiser Permanente Northern California facility during the study period from August 2018 through April 2020
Key exclusion criteria (2 listed)
- Children <18 years old
- Adults ≥65 years old
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Flublok QuadrivalentFlublok Quadrivalent vaccine is a recombinant hemagglutinin influenza vaccine indicated for active immunization against disease caused by influenza A subtype viruses and type B viruses contained in the vaccine for adults 18 years of age and older. Use of recombinant DNA techniques to produce vaccine antigen expressed in cell culture is a method that avoids growing the influenza viruses in embryonated hen's eggs. | Biological | Flublok Recipients |
| Standard Dose Inactivated Influenza Vaccine (SD-IIV)For the 2018-2019, 2019-2020, and 2020-2021 flu seasons, the primary SD-IIVs used will be Fluarix Quadrivalent and Flulaval Quadrivalent. | Biological | SD-IIV Recipients |
Primary outcome
Number of Adults 50-64 Years Old With Polymerase-chain Reaction (PCR) Confirmed Influenza Tests
Time frame: Up to 8 months
Patients who receive either Flublok or SD-IIV will be retroactively assessed for whether they had a PCR-confirmed positive influenza test (≥14 days after vaccination) as recorded in their electronic medical record by the end of the influenza season (April 30).
5 secondary outcomes
Number of Adults 50-64 Years Old Hospitalized With PCR-confirmed Influenza
Time frame: Up to 8 months
Number of Adults 50-64 Years Old Hospitalized With Community-acquired Pneumonia
Time frame: Up to 8 months
Number of Adults 50-64 Years Old Hospitalized With Cardio-respiratory Events
Time frame: Up to 8 months
Number of Adults 50-64 Years Old With Polymerase-chain Reaction (PCR) Confirmed Influenza A Tests
Time frame: Up to 8 months
Number of Adults 50-64 Years Old With Polymerase-chain Reaction (PCR) Confirmed Influenza B Tests
Time frame: Up to 8 months
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 Apr 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 39512761Hsiao A, Yee A, Izikson R, Fireman B, Hansen J, Lewis N, Gandhi-Banga S, Selmani A, Talanova O, Kabler H, Inamdar A, Klein NP. Safety of quadrivalent recombinant influenza vaccine in pregnant persons and their infants. AJOG Glob Rep. 2024 Sep 20;4(4):100395. doi: 10.1016/j.xagr.2024.100395. eCollection 2024 Nov.
- Derived from this study: PubMed 38091531Hsiao A, Yee A, Fireman B, Hansen J, Lewis N, Klein NP. Recombinant or Standard-Dose Influenza Vaccine in Adults under 65 Years of Age. N Engl J Med. 2023 Dec 14;389(24):2245-2255. doi: 10.1056/NEJMoa2302099.
- Derived from this study: PubMed 34998605Hsiao A, Hansen J, Nunley KV, Lewis N, Selmani A, Inamdar A, Mallett-Moore T, Izikson R, Rudin D, Klein NP. Safety of recombinant quadrivalent influenza vaccine compared to inactivated influenza vaccine in Chinese adults: An observational study. Vaccine. 2022 Jan 31;40(5):774-779. doi: 10.1016/j.vaccine.2021.12.035. Epub 2022 Jan 6.
- Individual participant dataSharing planned: No. All data reported to Sanofi Pasteur by the Kaiser Permanente Northern California Vaccine Study Center will be deidentified and aggregated.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Nicola P Klein, MD, PhD principal investigator
Kaiser Permanente
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Influenza and Pneumonia, run by Kaiser Permanente at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 8 Apr 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 8 Apr 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of Adults 50-64 Years Old With Polymerase-chain Reaction (PCR) Confirmed Influenza Tests (time frame: Up to 8 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03694392, which also lists 3 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 8 Apr 2025.