Overview
Public health campaigns continue to seek effective ways to increase COVID-19 vaccination among adults. A recent randomized controlled trial tested two theory-informed messaging approaches—attitudinal inoculation and cognitive behavioral therapy (CBT) kernel messaging—against standard public health messaging to see which could elevate vaccine uptake or readiness. The study focused on adults in the United States who had received at least one prior COVID-19 vaccine dose but were not up to date for the latest season.
Study Design and Population
The trial was a 3-arm, parallel-group, assessor-blinded randomized experiment conducted in 2024. Participants (n around 1,400) were drawn from a diverse national cohort and stratified by anxiety or depression symptoms. They were randomly assigned to one of three brief videos (each under 1 minute): (1) attitudinal inoculation, (2) CBT kernel messaging, or (3) standard public health messaging. After viewing, participants received reminders and were followed for 4 weeks to assess vaccine uptake and willingness.
Messaging Interventions
– Attitudinal inoculation aimed to strengthen defenses against misinformation by presenting common mis- and disinformation about vaccine effectiveness and refuting it with facts and logic.
– CBT kernel messaging linked problematic thoughts to vaccination behavior, modeling adaptive reasoning to overcome cognitive barriers and time constraints, particularly for those with anxiety or depressive symptoms.
– Standard messaging served as a control, reflecting conventional public health communications without inoculation or CBT elements.
Outcomes Measured
The primary outcome was receipt of a COVID-19 vaccine dose within 4 weeks. Secondary outcomes included vaccination willingness and post-intervention intent to vaccinate. Analyses followed the intention-to-treat principle, with multiple imputation for missing data and risk ratios (RR) and risk differences (RD) computed via Poisson models. Subgroup analyses examined participants with moderate-to-severe anxiety or depression symptoms.
Key Findings
Overall vaccination uptake at 4 weeks was low and did not differ significantly across arms: roughly 1% of the sample received a vaccine dose, with vaccination rates between arms showing no meaningful separation. Willingness to vaccinate at 4 weeks was also similar across groups, with no robust differences between the inoculation, CBT kernel, and standard messaging arms. These results held true for participants with and without mental health symptoms, though post hoc findings hinted that inoculation messaging might modestly boost willingness among those particularly worried about COVID-19.
Interpretation and Implications
The trial highlights the challenges of moving from improved attitudes to actual vaccination, especially among adults who are already partially vaccinated but not up to date. While attitudinal inoculation and CBT kernels are theoretically promising—aiming to reduce susceptibility to misinformation and to address cognitive barriers—the study found limited impact on short-term vaccine uptake in a period of low disease activity. The findings suggest several takeaways for future public health messaging:
- Short, theory-driven videos alone may be insufficient to drive substantial behavior change, particularly when baseline uptake is low.
- Inoculation strategies might show value in specific subgroups (e.g., those with heightened worries about COVID-19), warranting tailored messaging with careful targeting.
- CBT-based messaging could require ongoing engagement or integration with broader behavioral support to translate attitudes into action.
Limitations and Next Steps
The study occurred after the peak of the pandemic when overall risk perception and vaccine demand were relatively low. The brief intervention format, timing, and population characteristics may have constrained effect sizes. Future research could explore longer messaging, real-time high-transmission periods, and combinations of messaging with logistical supports (e.g., easier access to vaccination sites) to enhance uptake. Follow-up data beyond 4 weeks may reveal longer-term effects not captured in this trial.
Conclusion
Although this trial did not demonstrate clear advantages for attitudinal inoculation or CBT kernel messaging over standard messaging in boosting 4-week vaccine uptake, it contributes valuable evidence about how theory-based communication translates into real-world vaccination behavior. The results underscore the need for more nuanced, targeted, and sustained strategies to promote COVID-19 vaccination among adults, including those with mental health symptoms.
