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Completed

NCT Number: NCT07172074

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

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.

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Key information

Conditions

Vaccination Behavior Health Behavior Psychological Aspects Treatment Adherence and Compliance Treatment Refusal Vaccination Hesitancy Vaccination Promotion Vaccination Refusal

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Iowa

Iowa City, Iowa, 52242, United States

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

General Psych Trait Measure

Diagnostic Test

Respondents were randomized to answer whether psychological trait questions were general or about vaccines

Vaccine-Specific Psych Trait Measures

Other

Respondents were randomized to answer whether psychological trait questions were general or about vaccines

Primary outcomes

  1. Vaccine attitudes

    Time frame: Day 1

    Feelings towards vaccines on a 7-point scale, with Very negative (1) and Very positive (7) as the scale anchors

  2. Vaccination History

    Time frame: Day 1

    Indicated if they had received up to 7 age-recommended vaccines (Response options: No, Yes, Don't know/Unsure)

Secondary outcomes

  1. Psychological trait measures

    Time frame: 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

  2. 7C Antecedents to Vaccination

    Time frame: Day 1

    Single item to measure each antecedent to vaccination

  3. Attitudes towards Complementary and Alternative Medicine

    Time frame: Day 1

    6 item measure

  4. Personal Characteristics/Demographics

    Time frame: 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

Sponsors and collaborators

Lead sponsor

University of Iowa

Other

Collaborators

  • National Institute on Aging (NIA)

Registry information

Official study title

Improving Vaccine Outcomes in Older Adults-Quantitative

Important dates

Study start
2022
Primary completion
2025
Study completion
2025
First posted
Sep 15, 2025
Registry last updated
Sep 16, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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