Psychiatry · Medical Literature
Effectiveness of a video-based intervention for COVID-19 vaccine acceptance among individuals with mental disorders: a randomized online experiment.
Abstract
During the COVID-19 pandemic, vaccine hesitancy and low risk awareness were also observed in high-risk groups, such as individuals with mental disorders. This study evaluated an educational video aimed at increasing COVID-19 vaccine acceptance in this population. A randomized online experiment with 639 participants from the German general population (M Age = 37.04; 77.8% female; 24.4% self-reporting a mental disorder) was conducted during the second year of vaccine distribution. Participants were randomly assigned to either the educational video or a control group (no video). Outcomes included vaccination willingness, threat perceptions, and vaccine-specific beliefs. Moderation analyses examined differential effects for diagnostic status and internalizing psychopathology. The intervention significantly increased awareness of the importance of vaccination for individuals with mental disorders (p = 0.033, d = 0.17), perceived severity of COVID-19 (p = 0.010, d = 0.21), and deliberative decision-making (p = 0.015, d = 0.19). However, it did not significantly increase vaccination willingness or change vaccine-specific beliefs. Moderation analyses showed that participants with a self-reported mental disorder had greater perceived susceptibility (p = 0.032, d = 0.36), but internalizing psychopathology did not influence outcomes. While the video improved awareness and threat perceptions, further efforts are needed to address vaccine hesitancy and motivate behavior change in high-risk populations.
Clinical relevance
Does a brief educational video intervention increase COVID-19 vaccination willingness, threat perceptions, and vaccine-specific health beliefs among individuals with mental disorders recruited from the German general population? __SNAPSHOT__ {"studyDesign":"Randomized controlled online experiment (two-arm: educational video vs. no-video control)","setting":"Germany; online experiment conducted during the second year of COVID-19 vaccine distribution; affiliated with the Department of Clinical Psychology, Psychotherapy, and Experimental Psychopathology, Johannes Gutenberg University Mainz","sampleSize":"n = 639 total (intervention arm and control arm sizes not individually reported in the abstract)","population":"German general population adults; mean age 37.04 years; 77.8% female; 24.4% self-reporting a mental disorder. Participants with and without mental disorders were included, with subgroup analyses focused on those with self-reported diagnoses and on dimensional internalizing psychopathology.","intervention":"A single, brief educational video targeting COVID-19 vaccine acceptance, focused on the importance of vaccination for individuals with mental disorders, perceived disease severity, and deliberative decision-making","comparator":"No-video control group (passive/waitlist control)","primaryOutcome":"Vaccination willingness; secondary outcomes included threat perceptions (perceived susceptibility, perceived severity of COVID-19), awareness of the importance of vaccination for individuals with mental disorders, deliberative decision-making, and vaccine-specific beliefs","followUp":"Not reported (single-session online experiment; no longitudinal follow-up described in the abstract)","fundingSource":"Not reported"}
Key findings
The educational video intervention produced statistically significant but small-magnitude effects on three secondary outcomes compared to the no-video control: awareness of the importance of vaccination for individuals with mental disorders (p = 0.033, Cohen's d = 0.17), perceived severity of COVID-19 (p = 0.010, d = 0.21), and deliberative decision-making (p = 0.015, d = 0.19). All three effect sizes fall in the small range by conventional benchmarks (Cohen's d < 0.2–0.5). The primary outcome — vaccination willingness — was not significantly increased by the intervention. Vaccine-specific beliefs were likewise not significantly changed. Moderation analyses revealed a significant interaction for diagnostic status: participants with a self-reported mental disorder demonstrated greater perceived susceptibility in response to the video (p = 0.032, d = 0.36), a small-to-moderate effect. In contrast, dimensional internalizing psychopathology (e.g., continuous anxiety/depression scores) did not significantly moderate any outcome. Absolute effect sizes (risk differences, NNT) and confidence intervals were not reported in the abstract and therefore cannot be calculated or reported here. No adverse events or safety concerns were described.
Practice implications
This randomized online experiment provides limited but hypothesis-generating evidence that a brief educational video can modestly shift certain cognitive antecedents of vaccine acceptance — specifically, perceived disease severity, awareness of vaccination importance, and deliberative decision-making — in a general-population sample enriched with individuals reporting mental disorders. However, the intervention did not achieve its most clinically meaningful target: increased vaccination willingness. The gap between shifting cognitive threat appraisals and changing behavioral intentions is well-documented in health psychology (the intention-behavior gap), and this study does not resolve it. The moderation finding — that those with a self-reported mental disorder showed greater perceived susceptibility (d = 0.36) — is arguably the most clinically relevant signal, suggesting that targeted educational content may resonate more strongly with those who self-identify as having a mental health condition. However, this subgroup finding should be interpreted with caution given the exploratory nature of moderation analyses and the risk of Type I error. Importantly, mental disorder status relied entirely on self-report without clinical verification, limiting diagnostic precision. The sample was drawn from an online panel, was predominantly female (77.8%), and was German — restricting generalizability to other genders, clinical populations, and healthcare systems. No follow-up data on actual vaccination behavior were collected, so whether the observed cognitive shifts translated into real-world uptake remains unknown. Only an abstract was available for full appraisal; additional methodological details, scale properties, randomization procedures, and full moderation tables could not be independently verified. __LIMITATIONS__ Primary outcome (vaccination willingness) was not significantly improved, representing a null finding on the most clinically relevant endpoint.,Mental disorder status was determined by self-report only, without clinical interview or validated diagnostic instrument — a major measurement validity concern.,Sample was heavily female (77.8%), limiting generalizability to male and non-binary individuals.,Online convenience panel from the German general population may not represent clinical psychiatric populations (e.g., patients with psychosis, severe depression, or those not engaged with digital platforms).,No longitudinal follow-up: it is unknown whether cognitive changes translated into actual vaccination behavior.,All effect sizes are small (d = 0.17–0.21 for primary findings), and clinical meaningfulness of these changes on attitudinal scales is not established.,Moderation analyses were exploratory and susceptible to inflated Type I error without pre-specified correction for multiple comparisons.,Single-session intervention with no assessment of durability of effects.,Absolute effect sizes, confidence intervals, and NNT/NNH were not reported, precluding full quantitative appraisal.,Funding source not reported; potential conflicts of interest cannot be assessed.,Study was conducted during an acute phase of the COVID-19 pandemic; findings may have limited applicability to current or future vaccine hesitancy contexts.,Only an abstract was available; full methodological details (randomization, allocation concealment, blinding of assessors, attrition) could not be independently reviewed. __BOTTOM_LINE_CATEGORY__ promising_but_preliminary __BOTTOM_LINE__ A brief educational video produced small, statistically significant improvements in perceived COVID-19 severity, awareness of vaccination importance for those with mental disorders, and deliberative decision-making, but did not increase the primary outcome of vaccination willingness in a German online sample. The most clinically interesting signal is that individuals who self-identified as having a mental disorder showed greater perceived susceptibility in response to the video (d = 0.36), though this is based on self-reported diagnosis and exploratory moderation. This study does not provide sufficient evidence to change practice, but suggests that targeted educational video content meriting further investigation in clinically verified psychiatric populations with behavioral vaccination outcomes.