Influenza, Vaccine Hesitancy
Conditions
Brief summary
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.
Interventions
BEHAVIORALText messaging
Patients will receive up to 3 text messages reminding them about the importance of influenza vaccination during the 2022-2023 flu season.
Sponsors
National Institute on Aging (NIA)
University of California, Los Angeles
Los Angeles County Department of Public Health
University of Southern California
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
SINGLE (Caregiver)
Eligibility
Sex/Gender
ALL
Age
6 Months to No maximum
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Number of Participants Vaccinated at the End of the Campaign Period | 6 months | Number of Participants who received their influenza vaccination during the campaign period, as measured in the California Immunization Registry (CAIR2) to include vaccinations occurring both inside and outside the LADHS system. We assessed baseline vaccination status at the beginning of the flu season and excluded individuals who already received their vaccination. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Heterogeneity of Treatment Effects for Demographics | 6 months | Heterogeneity of treatment effects for demographic groups (previous vaccination status: vaccinated or unvaccinated) |
Countries
United States
Participant flow
Pre-assignment details
Only one household member (index person) is randomized and all other members receive the same message
Participants by arm
| Arm | Count |
|---|---|
| Standard Texts 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.
Text messaging: Patients will receive up to 3 text messages reminding them about the importance of influenza vaccination during the 2022-2023 flu season. | 121,743 |
| Standard Texts With Transportation Messaging 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#.
Text messaging: Patients will receive up to 3 text messages reminding them about the importance of influenza vaccination during the 2022-2023 flu season. | 3,050 |
| Total | 124,793 |
Baseline characteristics
| Characteristic | Standard Texts | Standard Texts With Transportation Messaging | Total |
|---|---|---|---|
| Age, Continuous | 45.27 years STANDARD_DEVIATION 19.68 | 45.25 years STANDARD_DEVIATION 19.78 | 45.27 years STANDARD_DEVIATION 19.68 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 69637 Participants | 1741 Participants | 71378 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 32141 Participants | 776 Participants | 32917 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 19965 Participants | 533 Participants | 20498 Participants |
| Region of Enrollment United States | 121743 Participants | 3050 Participants | 124793 Participants |
| Sex/Gender, Customized Sex/Gender Female | 62819 Participants | 1595 Participants | 64414 Participants |
| Sex/Gender, Customized Sex/Gender Male | 55271 Participants | 1363 Participants | 56634 Participants |
| Sex/Gender, Customized Sex/Gender Unknown/Not reported | 3653 Participants | 92 Participants | 3745 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 121,743 | 0 / 3,050 |
| other Total, other adverse events | 0 / 121,743 | 0 / 3,050 |
| serious Total, serious adverse events | 0 / 121,743 | 0 / 3,050 |
Outcome results
Primary
Number of Participants Vaccinated at the End of the Campaign Period
Number of Participants who received their influenza vaccination during the campaign period, as measured in the California Immunization Registry (CAIR2) to include vaccinations occurring both inside and outside the LADHS system. We assessed baseline vaccination status at the beginning of the flu season and excluded individuals who already received their vaccination.
Time frame: 6 months
Population: As not all randomized participants were eligible for the transportation messaging given their insurance did not cover healthcare transportation costs, these households were removed from both groups.
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| Standard Texts | Number of Participants Vaccinated at the End of the Campaign Period | 33357 Participants |
| Standard Texts With Transportation Messaging | Number of Participants Vaccinated at the End of the Campaign Period | 854 Participants |
p-value: 0.2162 proportion Z-test
Secondary
Heterogeneity of Treatment Effects for Demographics
Heterogeneity of treatment effects for demographic groups (previous vaccination status: vaccinated or unvaccinated)
Time frame: 6 months
Population: As not all randomized participants were eligible for the transportation messaging given their insurance did not cover healthcare transportation costs, these households were removed from both groups.
| Arm | Measure | Category | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Standard Texts | Heterogeneity of Treatment Effects for Demographics | Previously vaccinated | 44742 Participants |
| Standard Texts | Heterogeneity of Treatment Effects for Demographics | Previously unvaccinated | 77001 Participants |
| Standard Texts With Transportation Messaging | Heterogeneity of Treatment Effects for Demographics | Previously vaccinated | 1129 Participants |
| Standard Texts With Transportation Messaging | Heterogeneity of Treatment Effects for Demographics | Previously unvaccinated | 1921 Participants |
Comparison: Previously vaccinatedp-value: 0.342 proportion Z-test
Comparison: Previously unvaccinatedp-value: 0.2472 proportion Z-test