Precision Vaccine Promotion in Underserved Populations

Study Overview
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Brief Summary
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Previous studies have shown that low-cost, behavioral nudges through texting can increase influenza vaccination uptake compared to usual care. However, there are limited studies that evaluate the effect of decreasing barriers to scheduling, especially within safety net populations. The setting for this study, DHS, is the second largest public delivery system in the country and serves approximately half a million diverse patients that are eligible for vaccinations annually. This pilot study (one arm in a larger randomized controlled trial) will examine the effect of text messages highlighting MediCal health plan transportation resources (vs standard text messaging) on influenza vaccination rates in adults during the 2022-2023 flu season.

Official Title
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Precision Vaccine Promotion in Underserved Populations

Conditions
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Influenza, Vaccine Hesitancy

Intervention / Treatment
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* Behavioral: Text messaging


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Los Angeles County Department of Health Services (LACDHS) primary care patients over 6 months of age Exclusion Criteria: LACDHS patients less than 6 months of age

Ages Eligible for Study
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Minimum Age: 6 Months

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Standard Texts<br>Patients randomized to this study arm will receive a standard text reminding them about the importance of influenza vaccination. The standard texts will include a clinic call back number and patient portal self-scheduling for patients to schedule their influenza vaccines: #FirstName#, your flu shot is ready! Call your clinic at #ExternalRefNo# or visit the LA Health Portal at http://bit.ly/BookFluShot if you want this shot held for you. | Behavioral: Text messaging<br>* Patients will receive up to 3 text messages reminding them about the importance of influenza vaccination during the 2022-2023 flu season.<br>|
| Experimental: Standard Texts with Transportation messaging<br>Patients randomized to this study arm will receive standard texts plus transportation messaging including a phone number for patients to reserve transportation to a vaccination appointment based on MediCal health plan transportation resources: #FirstName#, your flu shot is ready! Call your clinic at #ExternalRefNo# or visit the LA Health Portal at http://bit.ly/BookFluShot if you want this shot held for you. You can call #Health Plan Phone Number# to schedule a free ride for your flu shot through #HealthPlanName#. | Behavioral: Text messaging<br>* Patients will receive up to 3 text messages reminding them about the importance of influenza vaccination during the 2022-2023 flu season.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Vaccination status at the end of the campaign period | Vaccination status at the end of the campaign period, as measured in the California Immunization Registry (CAIR2) to include both inside and outside vaccinations | 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heterogeneity of treatment effects for demographics and distance | Heterogeneity of treatment effects for demographic groups and distance to health systems | 6 months |