Views on vaccines range from those who are strongly supportive to those who are stridently opposed and will not budge from identity-based core beliefs about vaccines. In between these poles are numerous others who can delay, be reluctant (but still accept), or refuse/accept some vaccines for their children but not others. It is for these vaccine-hesitant parents that constitute the 'middle ground' of this spectrum where the most immediate and productive gains can be made towards enhancing vaccination acceptance and improving uptake. However, navigating this noisy communications environment is difficult, given the array of confusing and conflicting information available from multiple and competing sources. To date, there is no consensus on how best to use communication to respond to vaccine hesitancy. Building on two Canada-wide surveys of parents, the goal of this research is to identify which communication strategies show the greatest impact in reducing parental vaccine hesitancy and improving vaccination intentions.

The specific objectives are to:

1. Develop and pre-test four variations of news media stories that vary by source (parent versus physician) and content (intuitive versus deliberative);
2. Examine the impact of vaccine hesitant parents' exposure to vaccine communications that vary in source (parent versus physician) and content (intuitive versus deliberative) on primary (vaccine hesitant attitudes) and secondary (vaccine intentions) outcomes; and
3. Explore which media story variation may be more effective in improving vaccination attitudes and intentions for different parental decision-making styles (deliberative versus intuitive).

Inclusion Criteria:

• Parents over 18 living in Canada with a YOUNGEST child is less than 24 months.

Exclusion Criteria:

• Parents who have a YOUNGEST child older than 24 months
• A parent who is pregnant, before the first trimester is complete

Statisticians completing the analysis of the primary outcome will be blinded.