Improving Influenza Vaccination Delivery Across a Health System by the Electronic Health Records Patient Portal RCT 6
Phase: NA
Conditions: Influenza, Respiratory Tract Infections
Sponsor: University of California, Los Angeles

Study Title: Improving Influenza Vaccination Delivery Across a Health System by the Electronic 
Health Records Patient Portal RCT 6 
Initial IRB Approval: 12/20/2017 
RCT 6 IRB Approval: 08/11/2023 
Clinical Trials Registration: NCT06062264 
 
 

 
Brief Summary: 
This trial is taking place in Los Angeles, CA at 21 clinics within the UCLA Health System. 
The study design is a 3 arm randomized trial. Patients will be randomized into 1) receiving portal 
based reminder messages with a video from their PCP encouraging them to receive the 
influenza vaccine, 2) portal-based reminder messages with an infographic with the image of 
their PCP encouraging them to receive the influenza vaccine, or 3) the control group. Patients 
randomized to the intervention arms will receive reminders if they are due for influenza vaccine. 
Despite the Advisory Committee on Immunization Practices (ACIP) recommendation in 2010 
that all people above 6 months of age should receive an annual flu vaccine, vaccination rates 
remain low: at 6m-4.9 yrs. (70%), 5-17.9 yrs. (56%), 18-64.9 yrs. (38%), and >65 yrs. (63%). 
The investigators will assess the effectiveness of MyChart R/R video messages and infographic 
messages as compared to the standard of care control (Health system messages). 
Methods and Procedures 
This randomized controlled trial will assess the effectiveness of reminders messages sent to 
portal users, encouraging influenza vaccination, on increasing influenza vaccination rates within 
a health system. Patients will be randomized into three groups: 1) one-third of patients will 
receive reminder messages with a video from their PCP encouraging them to receive the 
influenza vaccine, 2) one-third will receive reminders with an infographic with information about 
the influenza vaccine with an image of their PCP, and 3) one-third will receive standard health 
system messages (standard of care). 
Portal-based video messages: Clinicians have been shown to be trusted by their patients, so by 
sending patients videos that have been recorded by their own primary care physician, we are 
testing the concept of 'trusted messengers' to improve influenza vaccine uptake. 
Portal-based infographic messages: This study arm is also testing the concept of 'trusted 
messenger' since all infographic messages will also have an image of patients' own primary 
care physician at the top. 
Interventions that apply Behavioral Economics principles in vaccine promotion messaging can 
increase vaccine receipt. In the physician videos and infographics we will also include language 
utilizing the concepts endorsing social norms, social good, positive framing, urgency, and 
planning. 
For the primary analysis, the primary outcome will be the patient's end of flu season vaccination 
status. Intervention effects will be assessed using mixed effects log-binomial models. 
The portal-based reminder messages will be sent in October of 2023. Repeat messages will 
also be sent in late October, and late November to patients who do not receive their influenza 
vaccines. 
Eligibility: Our EHR will identify subjects who are eligible for either 1 or 2 influenza vaccinations 
based on ACIP algorithms (2 are recommended for children <9 years who have not had prior 
vaccination). 

Inclusion criteria 
Inclusion criteria will involve-- all patients over 6 months of age who have made at least 1 visit to 
the practice within the prior 3 years and who have signed up for MyUCLAhealth (UCLA’s portal) 
and have used the portal at least once within 12 months. Currently this includes 145,684 
patients. 
a. Active patient: We selected >1 visit in 3y based on our prior studies and the literature to focus 
the intervention on active patients; practices do not have a good mechanism to inactivate 
patients.  
b. Focusing on Portal Users: We can only send portal R/R messages to patients who have 
signed up for the portal. Since some patients sign up for the portal but never use it we will 
restrict our inclusion criteria to patients who used the portal within 12m (53% of UCLA patients). 
This standard has been applied before. We will assess intervention effects for the included 
population, and also for the entire practice, since the impact of the intervention reflects the 
extent of portal penetration.  
Exclusion criteria 
Patients will be excluded if they are not a patient at one of the 49 primary care practices within 
UCLA’s Health System, and/or if they do not meet the above specified requirements for being 
an active patient or portal user. 
Main Outcomes and Measures 
Primary Measure: Receipt of >1 influenza vaccine as documented in the EHR which is 
supplemented electronically by the health system with influenza vaccination data from external 
sources (e.g., pharmacies).   
Participant Group/Arm  
Intervention/Treatment  
Active Comparator: Portal-Based 
PCP Video Reminder Message 
Participants in their arm will receive 
up to 3 portal-based messages with a 
video recorded message from their 
own primary care physician 
encouraging them to receive the 
influenza vaccine. 
Behavioral: Portal-based Video Message 
• 
Video recorded by physician 
encouraging patients to receive 
influenza vaccine. Sent via the patient 
portal. 
Active Comparator: Portal-Based 
PCP Infographic Reminder Message 
Participants in their arm will receive 
up to 3 portal-based messages with 
an infographic message with an 
image of their own primary care 
Behavioral: Portal-based Infographic Message 
• 
Infographic with information about the 
influenza vaccine and an image of the 
physician. Sent via the patient portal. 

physician encouraging them to 
receive the influenza vaccine. 
No Intervention: Standard Health 
System Portal Messages 
Participants in this arm will only 
receive standard-of-care health 
system portal messages, and will not 
receive study-based messages.