Effectiveness of an online vaccine misinformation game for Arabic-speaking Australians: a randomized controlled trial

Vaccine misinformation can undermine vaccine confidence, institutional trust, and uptake. Arabic speakers in Australia are disproportionately susceptible to vaccine misinformation and have experienced adverse health outcomes. This randomized controlled trial tested the effectiveness of Cranky Uncle - Vaccine (Arabic), a gamified psychological inoculation intervention, in improving vaccine attitudes, misinformation discernment, and institutional trust among Arabic-speaking Australians.

Participants (N = 198) were randomized 1:1 to either the intervention (game) or control (educational climate change video). Outcomes were assessed immediately and 3 weeks post-activity using a combination of validated and custom instruments: (1) the Vaccine Trust Indicator (VTI); (2) a misinformation discernment scale developed by the research team, and (3) items from the Institutional Trust subscale. Analyses were conducted using multiple imputation and adjusted linear regression models. The trial protocol was registered in the Australian and New Zealand Clinical Trials Registry (registration number: ACTRN12624000934549p).

No statistically significant differences were found between the intervention and control groups at either timepoint across primary or secondary outcomes, and no subgroup effects were observed by age or education. Post-hoc item analyses found that items assessing trust in scientists and trust in pharmaceutical companies demonstrated the greatest difference between groups at the immediate post-activity timepoint.

This trial is the first RCT of the Cranky Uncle - Vaccine game. Findings highlight methodological and measurement challenges in misinformation research. Developing and validating standardized measures that are appropriately sensitive to detect meaningful changes should be an urgent priority for the field. Future evaluation of the Cranky Uncle intervention for different populations could consider testing delivery in structured educational group settings.