Effect of Messaging on Pragmatic Outcomes Within an Integrated Healthcare System

ConditionCovid-19 Vaccination

Trial statusNot yet recruiting

Trial phaseNot applicable

Trial typeInterventional

Biological sexAll

Age18+

SponsorKaiser Permanente

About this trial

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.

Eligibility criteria

This trial accepts healthy volunteers

Qualifiers

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;

Disqualifiers

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.

Trial design

Design model

Parallel

Treatments tested in this trial

Vaccine choice message
Behavioral
A message communicating available choices of COVID-19 vaccines.
Vaccine choice + platform-framed message
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
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
Behavioral
A message communicating available choices of COVID-19 vaccines and expected side effects of available vaccines.

Treatment groups

1,300,000 Participants

are divided into 5 treatment groups

Group A: Usual CareNo intervention 0 interventions

Group B: A. Choice-framedExperimental treatment 1 intervention

Group C: B. Choice + vaccine platform-framedExperimental treatment 1 intervention

Group D: C. Choice + HCP trust-framedExperimental treatment 1 intervention

Group E: D. Choice + reactogenicity-framedExperimental treatment 1 intervention

Trial outcomes

Primary outcomes

Proportion of participants with documented receipt of the updated 2026-27 COVID-19 vaccine

Kaiser Permanente Southern California's electronic health record tracks the type of vaccine, dose, and date each patient receives. Immunization data will be retrieved from participants' electronic health records to ascertain COVID-19 immunization status during the study period.

Time frame