Comparing Relative Strengths of Statistical Associations Between Psychological Traits and Vaccination-Related Outcomes I

Not Applicable

Completed

• Conditions: Vaccination; Vaccination Hesitancy; Vaccination Promotion; Psychological Aspects

• Registration Number: NCT07172074
• Lead Sponsor: University of Iowa

Brief Summary

The goal of this study was to identify psychological motives that had the strongest statistical associations with vaccine outcomes in order to identify novel intervention targets to be used in vaccine promotion efforts. A national sample of US adults completed an online survey containing a variety of vaccine-related measures and psychological trait measures.

Detailed Description

A national sample of US adults were recruited through Dynata, an online survey panel company, to complete an online survey. Participants completed a variety of vaccine-related survey items and an unprecedented number (\>20) of psychological trait measures. This was possible by using a Planned Missingness Design, where respondents only answer a predetermined subset of survey questions, which allows us to include more measures without significantly increasing the burden for participants.

Participants were randomized to one of the three question blocks, where each block had a predetermined set of items that were roughly 1/3 of the items from each psychological trait measure. They were also randomized to complete questions that were about the psychological traits in general or about vaccines specifically.

Study Timeline

• Study Start: 2022-12-30
• Primary Completion: 2023-02-27
• Study Completion: 2023-02-27
• Status Verified: 2025-09
• Study First Submitted: 2025-09-03
• Study First Submitted QC: 2025-09-10
• Last Update Submitted: 2025-09-10
• Study First Posted: 2025-09-15
• Last Update Posted: 2025-09-15

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 1786

Inclusion Criteria

• Consent to participate
• Agree to provide quality responses

Exclusion Criteria

• Quota completed (Equal #s of respondents in each group)

  • Age group: 18-49, 50-64, 65+
  • Race/ethnicity: Non-Hispanic White, Non-Hispanic Black, Hispanic
  • Income: <$50K, $50K or more
  • Gender: Female, Male or other gender identity

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: FACTORIAL

Primary Outcome Measures

Name	Time	Method
Vaccine attitudes	Day 1	Feelings towards vaccines on a 7-point scale, with Very negative (1) and Very positive (7) as the scale anchors
Vaccination History	Day 1	Indicated if they had received up to 7 age-recommended vaccines (Response options: No, Yes, Don't know/Unsure)

Secondary Outcome Measures

Name	Time	Method
7C Antecedents to Vaccination	Day 1	Single item to measure each antecedent to vaccination
Psychological trait measures	Day 1	26 measures: Needle phobia, Disgust sensitivity, Distrust, Conspiratorial mindset, Medical ambiguity aversion, Open-minded thinking, Self-protection motivation, Psychological reactance, 7 Moral Foundations, Self-construal, Social dominance orientation, Misinformation susceptibility, Faith in intuition, Delay discounting, Outcome bias, Scientific knowledge, Subjective numeracy, Health literacy, Medical maximizing-minimizing, Emotional reactivity to rare events
Attitudes towards Complementary and Alternative Medicine	Day 1	6 item measure
Personal Characteristics/Demographics	Day 1	16 characteristics: Gender, Age, Race/ethnicity, Income, State of residence, Zip code, Relationship status, Education, Work in medical field, Economic political ideology, Social political ideology, Political party affiliation strength, Religiosity, Religious ideology, Subjective health, Health conditions

Trial Locations

Locations (1)

University of Iowa; 🇺🇸 Iowa City, Iowa, United States