Moral foundations messaging to improve vaccine attitudes: An online randomized experiment from Argentina

PLOS Glob Public Health. 2024 Nov 15;4(11):e0003276. doi: 10.1371/journal.pgph.0003276. eCollection 2024.

Abstract

The uptake of routine childhood vaccinations has declined globally since the start of the COVID-19 pandemic, due in part to increased vaccine hesitancy among parents. The Moral Foundations Theory proposes six foundations which can be targeted to increase vaccine uptake. In this study, we tested whether a post by UNICEF with a purity violation message could affect vaccine attitudes among parents in Argentina, where routine immunization coverage has been declining since 2014. Using an online randomized controlled survey experiment, we included 1,511 parents with a child under 12 years in Argentina. Outcomes were measured on the Vaccine Trust Indicator (VTI). We found that the purity violation message significantly affected vaccine attitudes: 80% of the intervention group scored high on the Vaccine Trust Indicator, compared to 73% in the control group (coefficient: 0.33, 95% Confidence Interval 0.20-0.47). Vaccine messaging framed as a purity violation is a promising way to improve vaccine attitudes among parents.

Grants and funding

Thus study was amended as part of the authors' Insights for Impact work, conducted in partnership with UNICEF (contract #43329087) as part of the Vaccine Acceptance Interventions Laboratory (VAIL) component of the Vaccination Demand Observatory. SBO was the Principal Investigator, and HM, SC, MW, and SBO were funded on the award to conduct the research. The funder (UNICEF) did not have a role in the study design or data analysis, but the UNICEF country offices (LL, NA) had significant input into the audience targeting and messaging interventions that were tested.