An Online Application to Explain Community Immunity with Personalized Avatars: A Randomized Controlled Trial

Area of Science:

• Public Health
• Health Communication
• Behavioral Science

Background:

• Community immunity, also known as herd immunity, is crucial for controlling vaccine-preventable diseases.
• Understanding community immunity is complex and can be challenging to communicate effectively to the public.

Purpose of the Study:

• To evaluate a web-based, personalized avatar intervention designed to convey the concept of community immunity.
• To assess the intervention's impact on risk perception, emotions, knowledge, and vaccination intentions across four vaccine-preventable diseases.

Main Methods:

• A 2x4 factorial randomized controlled trial involving 3883 Canadian adults.
• Development of a web application ('herdimm') using personalized avatars and animations to illustrate disease spread with and without community immunity.
• Comparison of the intervention group with a control group, analyzing primary outcomes (objective and subjective risk perception) and secondary outcomes (emotions, knowledge, vaccination intentions).

Main Results:

• The 'herdimm' intervention significantly increased objective risk perception (58.0% vs. 38.2%) and subjective risk perception (5.54 vs. 5.30).
• Participants in the intervention group showed increased emotions (worry, anticipated guilt), knowledge, and vaccination intentions compared to the control group.
• The positive effects of the intervention were more pronounced in individuals with collectivist orientations and sometimes negative in those with individualist orientations.

Conclusions:

• Web-based personalized avatar interventions can effectively enhance understanding of community immunity and promote positive health behaviors.
• Public health campaigns should consider tailoring messages about collective benefits to resonate with different cultural orientations, particularly collectivism.
• Personalized avatar interventions show promise for improving risk perception and vaccination intentions, especially among collectivist populations.