What this study is
COVID-19 vaccination among patients at high risk for severe disease has declined in the United States since 2022. Prior research, including discrete choice experiments (DCEs), has demonstrated that vaccine preferences are influenced by attributes such as effectiveness, safety, convenience, and protection against severe disease. Although DCEs provide valuable insights into stated vaccine preferences and decision-making, they rely on hypothetical scenarios and cannot directly assess how vaccine attributes influence real-world vaccine uptake. Additional research is needed to understand the relationship between vaccine characteristics and observed COVID-19 vaccination behavior in routine clinical practice.
The EMPOWeR study is a pragmatic randomized controlled trial conducted within Kaiser Permanente Southern California (KPSC) to evaluate the effect of immunization messages and reminders that highlight COVID-19 vaccine choices on vaccine uptake. The primary research questions are:
1. Does having a choice in COVID-19 vaccine platform affect vaccine uptake among patients at high-risk of severe disease? 1a. Does having a choice in COVID-19 vaccine platform affect vaccine uptake among patients at high-risk of severe disease, when differences in vaccine platform are highlighted? 1b. Does having a choice in COVID-19 vaccine platform affect vaccine uptake among patients at high-risk of severe disease, when a trusted healthcare professional (HCP) endorses both vaccine options? 1c. Does having a choice in COVID-19 vaccine platform affect vaccine uptake among patients at high-risk of severe disease, when vaccine reactogenicity is highlighted?
A secondary research question is: 2. Does having a choice in COVID-19 vaccine additionally increase uptake of influenza vaccine?
During the 2026-2027 respiratory virus season, eligible KPSC members who are at high-risk of severe COVID-19 will be randomly assigned to receive a standard reminder message or a reminder message with additional information about available COVID-19 vaccine options.
What's being tested
- Vaccine choice message
Intervention · BEHAVIORAL
A message communicating available choices of COVID-19 vaccines.
- Vaccine choice + platform-framed message
Intervention · BEHAVIORAL
A message communicating available choices of COVID-19 vaccines and differences in vaccine composition and mechanisms of protection by vaccine type.
- Vaccine choice + HCP trust-framed message
Intervention · BEHAVIORAL
A message communicating available choices of COVID-19 vaccines and emphasizes the support of healthcare personnel (HCP) for both vaccine options.
- Vaccine choice + reactogenicity-framed message
Intervention · BEHAVIORAL
A message communicating available choices of COVID-19 vaccines and expected side effects of available vaccines.
Study details
- Official title
- Effect of Messaging on Pragmatic Outcomes Within an Integrated Healthcare System: a Randomized Trial (EMPOWeR)
- Sponsor
- Kaiser Permanente
- Conditions
- Covid-19 Vaccination
- Enrolling
- 1,300,000 people
- Starts
- 2026-09-29
- Est. completion
- 2027-06-30
- Design
- Triple-blind, randomized, parallel groups
- Record
- View on ClinicalTrials.gov ↗
Who can join
Age 18 Years and overSex ALLHealthy volunteers AcceptedYou may qualify if
- Aged ≥18 years;
- Active KPSC member;
- Continuous membership from 27 August 2025 to 28 September 2026;
- Members who are aged 65 years and older, or adults aged 18-64 years with at least one of the following health conditions that increases their risk for severe COVID-19 illness, including: a) asthma, b) cancer, c) ischemic stroke, d) intracerebral or subarachnoid hemorrhage, e) transient ischemic attack, f) chronic kidney disease, g) dialysis, h) bronchiectasis, i) chronic obstructive, pulmonary disease (COPD), j) pulmonary fibrosis, k) cystic fibrosis, l) pulmonary hypertension, m) cirrhosis, n) non-alcoholic fatty liver disease (NALD), o) alcoholic liver disease, p) autoimmune hepatitis, q) diabetes, r) heart failure, s) coronary artery disease, t) cardiomyopathy, u) HIV, v) obesity, w) essential hypertension, x) primary immunodeficiency and other underlying immunocompromising conditions, y) solid organ or blood stem cell transplant, z) tuberculosis;
- No documented receipt of updated 2026-27 COVID-19 vaccine as of 28 September 2026;
- Has valid email information.
You can't join if
- Unable to receive or opted out of email communication.
- People with unknown or missing sex.
- People who cannot safely receive a COVID-19 vaccine, including those who had a severe allergic reaction to a previous COVID-19 vaccine or have a contraindication to COVID-19 vaccine or a vaccine ingredient, will not be included in the study.
- People with metastatic or terminal illness, advanced illness, receiving hospice or palliative care, or resident in skilled nursing facilities.
- People who are pregnant or currently breastfeeding.
Sign in and we'll check these against your records.Full criteria on ClinicalTrials.gov ↗
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Study locations (1)
1 openKaiser Permanente Southern California, Department of Research & Evaluation
Pasadena, California, United States
- Zendi S Yha, BS · Contact626-372-5637zendi.s.yha@kp.org
- Annette Regan, PhD, MPH · Contact626-760-2482annette.k.regan@kp.org
Recruiting
Study team
Sponsor
Kaiser Permanente
Study ID 14603
Principal investigator
Annette Regan, PhD
Kaiser Permanente
Frequently asked questions
The sponsor hasn't published answers to common questions for this trial.