Sequential Digital Intervention to Increase Influenza Vaccination in Patients With Heart Failure

Condition(s) studied

Investigational drug(s) / intervention(s)

Routine Influenza Vaccination Recommendation: A single standardized influenza vaccination recommendation is provided during the initial AI-assisted telephone call before first-stage randomization. The call also assesses contact status, survival status, and current-season vaccination status.

Repeated AI-Assisted Telephone Intervention: Participants assigned to the sequential digital intervention strategy receive additional AI-assisted telephone calls approximately 14 and 28 days after the initial call. Vaccination status is reassessed, and unvaccinated participants are asked about reasons for non-vaccination and receive a repeated vaccination recommendation. Further intervention is discontinued for participants confirmed to have been vaccinated.

Gain-Framed SMS Reminder: One gain-framed SMS message emphasizing the potential health protection associated with influenza vaccination is sent approximately 14 days after second-stage randomization to participants assigned to this strategy.

Loss-Framed SMS Reminder: One loss-framed SMS message emphasizing the potential loss of protection and continued influenza-related health risks associated with non-vaccination is sent approximately 14 days after second-stage randomization to participants assigned to this strategy.

Study summary

Influenza vaccination is an important preventive measure for patients with heart failure (HF), but vaccination uptake remains low in China. Although previous studies have demonstrated the benefits of actively promoting influenza vaccination, scalable strategies to improve vaccination uptake among patients with HF after hospital discharge remain insufficiently evaluated.

The PANDA-BOOST trial is a prospective, pragmatic, open-label, two-stage sequential randomized clinical trial involving participants previously enrolled in the PANDA II trial. The study aims to evaluate whether sequential digital interventions using artificial intelligence (AI)-assisted telephone calls and short message service (SMS) reminders improve influenza vaccination uptake compared with a single routine vaccination recommendation.

After an initial AI-assisted telephone call providing a standardized influenza vaccination recommendation, eligible unvaccinated participants will be randomized in a 1:2 ratio to a routine recommendation group or a sequential digital intervention group. Participants in the sequential intervention group will receive additional AI-assisted telephone calls approximately 14 and 28 days after the initial call. Those who remain unvaccinated and meet eligibility criteria at the third call will undergo a second randomization in a 1:1:1 ratio to no additional SMS, gain-framed SMS, or loss-framed SMS.

The primary outcome is influenza vaccination uptake within two months after the first-stage randomization.

Eligibility

Primary outcome measure(s)

• Influenza Vaccination Uptake — From first-stage randomization to 2 months after randomization
  The proportion of participants who receive the 2026-2027 seasonal influenza vaccine within two calendar months after first-stage randomization. Vaccination status will be determined primarily using vaccination registry data from the Beijing Center for Disease Prevention and Control. Participants with a qualifying vaccination record within the assessment window will be classified as vaccinated. Participants with adequate registry coverage but no qualifying record will be classified as unvaccinated. Outcomes that cannot be reliably ascertained will be recorded as indeterminate.

Trial sites (1)

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