Effect of Personalized Messages Sent by a Health System’s Patient Portal on Influenza Vaccination Rates: a Randomized Clinical Trial

Background: Adult influenza vaccination rates are low. Tailored patient reminders might raise rates. Objective: Evaluate impact of a health system’s patient portal reminders: (1) tailored to patient characteristics and (2) incorporating behavioral science strategies, on influenza vaccination rates among adults. Design: Pragmatic 6-arm randomized trial across a health system during the 2019–2020 influenza vaccination season. The setting was one large health system—53 adult primary care practices. Participants: All adult patients who used the patient portal within 12 months, stratified by the following: young adults (18–64 years, without diabetes), older adults (≥65 years, without diabetes), and those with diabetes (≥18 years). Interventions: Patients were randomized within strata to either (1) pre-commitment reminder alone (1 message, mid-October), (2) pre-commitment + loss frame messages, (3) pre-commitment + gain frame messages, (4) loss frame messages alone, (5) gain frame messages alone, or (6) standard of care control. Patients in the pre-commitment group were sent a message in mid-October, asking if they planned on getting an influenza vaccination. Patients in loss or gain frame groups were sent up to 3 portal reminders (late October, November, and December, if no documented influenza vaccination in the EHR) about importance and safety of influenza vaccine. Main Measures: Receipt of 1 influenza vaccine from 10/01/2019 to 03/31/2020. Key Results: 196,486 patients (145,166 young adults, 29,795 older adults, 21,525 adults with diabetes) were randomized. Influenza vaccination rates were as follows: for young adults 36.8%, for older adults 55.6%, and for diabetics 60.6%. On unadjusted and adjusted (for age, gender, insurance, race, ethnicity, and prior influenza vaccine history) analyses, influenza vaccination rates were not statistically different for any study group versus control. Conclusions: Patient reminders sent by a health system’s patient portal that were tailored to patient demographics (young adults, older adults, diabetes) and that incorporated two behavioral economic messaging strategies (pre-commitment and loss/gain framing) were not effective in raising influenza vaccination rates. Trial Registration: This trial was registered with ClinicalTrials.gov (NCT04110314).