Using positive imagination to reduce negativity in information processing and hesitant attitudes towards childhood COVID-19 vaccinations in parents: A randomized controlled trial

Objectives: We aim to investigate the impact of negative information processing on parental vaccine hesitancy in Hong Kong and design an intervention to reduce negativity in pandemic and vaccine-related information processing. Design: Six hundred and forty-seven parents were recruited for baseline assessment. One week later, participants were randomly assigned to either the positive imagination simulation (PIS) intervention group or the neutral recall simulation (NRS) control group. Participants completed outcome assessments immediately and 2 weeks after the intervention. Methods: We first examined whether affective response to pandemic and vaccine-related news mediated the association between parents' distress and acceptance of childhood COVID-19 vaccination using baseline data. The PIS intervention leveraged positive psychology and personalized imagery techniques to enhance positive affect. To test intervention effectiveness, ANCOVAs were conducted to examine whether PIS versus NRS could reduce negative affective response to pandemic and vaccine-related news (immediate effect) and COVID-19 vaccine-hesitant attitudes (effect at the 2-week post-intervention point). Results: The baseline assessment showed that greater distress was linked to a more negative affective response to pandemic and vaccine-related news, which was associated with lower acceptance for childhood COVID-19 vaccination. The intervention positively impacted valence rating (F(1, 627) = 8.46, p =.004) and affective state rating (F(1, 627) = 4.88, p =.028) on pandemic and vaccine-related news. This improved positivity spilled over to significantly enhance parents' trust in COVID-19 vaccine-related information and alleviate their vaccine safety concerns 2 weeks post-intervention. Conclusions: Our study highlights the promising impact of positive affect priming in increasing positivity in information processing and, consequently, reducing vaccine-hesitant attitudes that are modifiable through positive information processing.