372 - Narrative Reminder Recall to Improve Pediatric Influenza Vaccination: A Pilot Randomized Clinical Trial

Publication Number: 2361.372

Joshua T. Williams, Denver Health, Denver, CO, United States; Kate Kurlandsky, Denver Health, Denver, CO, United States; Neha Bharadwaj, University of Colorado School of Medicine, Aurora, CO, United States; Amy B. Stein, University of Colorado School of Medicine, Denver, CO, United States; Simon J. Hambidge, University of Colorado School of Medicine & Denver Health, Denver, CO, United States; Rocio Pereira, Denver Health, Denver, CO, United States; Sonja C. O'Leary, Denver Health, Denver, CO, United States; Sean T. O'Leary, University of Colorado School of Medicine, Denver, CO, United States

Background: Historically, reminder recall has been an effective strategy to improve pediatric influenza vaccination coverage. Recently, its effectiveness has been attenuated. Digital stories are brief, multimedia narratives that may enhance the effectiveness of traditional reminder recall strategies.

Objective: To (1) assess the reach of digital narrative reminders among caregivers of young children and (2) estimate their effect on child influenza vaccination.

Design/Methods: This was a pilot randomized controlled trial of a text message digital story intervention in 2 safety-net clinics in historically Black neighborhoods in Denver, CO (9/16/24 - 3/31/25). English-speaking caregivers ≥18 years old with children aged 6 months to 5 years old were recruited. Intervention caregivers received 7 texts in October 2024: 5 included messages with URL links to digital stories (URLs were unique for each caregiver), 2 had scheduling information. Control caregivers received a single electronic health record portal reminder (usual care systemwide in 2024-25).

The primary caregiver outcome was narrative reminder reach, defined as the proportion of caregivers who watched 1 or more digital stories. The primary child outcomes were time to first influenza vaccination in days, beginning 9/15/24, and first vaccination by peak influenza activity (2/15/2025). Adjusted Cox Proportional Hazards modeling fit time to vaccination by group and baseline covariates, including caregiver influenza vaccine hesitancy status. Kaplan-Meier curves analyzed the proportions of children becoming vaccinated by group over time, including by peak influenza activity.

Results: Intention to treat analyses included 200 children (100 per group; mean [SD] age 29.1 [16.1] months, 96 [48.0%] male, and 77 [38.5%] Black race) and 198 caregivers (98 usual care, 100 in DST; mean [SD] age 30.5 [7.5] years, 176 [88.9%] mothers, and 77 [38.9%] Black). Baseline characteristics were similar between groups (Table 1). Overall, 7/98 (7%) caregivers viewed ≥1 digital story. More children of intervention caregivers became vaccinated over the season (Figure 1; p = 0.04), including by peak influenza activity (38% vs. 26%; Z-test 1.82; p = 0.03). In adjusted analyses (Table 2), children of intervention caregivers were 63% more likely (aHR 1.63; 95% CI: 1.01, 2.64) to become vaccinated, referent to children of caregivers receiving usual care.

Conclusion(s): In a pilot randomized trial, narrative reminder recall had poor reach among caregivers but was associated with improved child influenza vaccination, compared to electronic portal messaging.

Table 1
Table_1.pdfSociodemographic information for study participants (N = 198 caregivers [98 intervention, 100 usual care]; N = 200 children [100 intervention, 100 usual care]).

Table 2
Table_2.pdfUnadjusted and adjusted multivariable cox proportional hazard ratios for likelihood of first influenza vaccination dose at any time point in the influenza season, defined as September 16, 2024 to March 31, 2025, using predefined independent variables.

Figure 1
Figure_1.pdfKaplan-Meier time to vaccination curves, stratified by caregiver study group, with 21.7 weeks from the start of influenza season (i.e. February 15, 2025, or peak influenza activity) represented with a vertical dashed line.