Role of social endorsement in attitudes towards a new health treatment: Results from a randomized vignette-based survey in Lesotho

We examined whether social endorsement from a close trusted individual can influence ambiguity attitudes towards a hypothetical new treatment. We conducted a vignette-driven 1:1 randomized survey experiment with 475 outpatient visitors at the district government hospital in Butha Buthe, Lesotho between March and September 2024. The primary outcome was measured using the Ambiguity Aversion Measure for Medical Treatments and Devices (AA-Med). A mixed-effects ordinal logistic regression was used to model the influence of social endorsement on AA-Med scores. Regression results revealed no differences in AA-Med scores based on the presence of social endorsement (β=0.06; 95% CI [-0.29 – 0.40]; p=0.70). Tertiary education was associated with lower ambiguity aversion after controlling for confounders (β=-1.17; 95% CI [-1.78 – -0.57]; p<0.01). In free text responses, participants reported that they had experienced aversion to new health services due to feeling uncertain (i.e., COVID vaccines, new HIV treatment regimen). Contrary to our hypothesis built on Western theories, social endorsements had no influence on ambiguity attitudes in Lesotho. Nevertheless, this study demonstrates the presence of pre-existing ambiguity aversion towards new treatments among outpatient visitors in Butha Buthe, Lesotho. The study informs how ambiguity aversion may be examined in a survey experiment in a low-resourced health context, including theoretically grounding the concept within the local context to enable a more nuanced investigation of ambiguity aversion among patients in this setting. Practice implications Providers and implementers of new treatments in Lesotho may consider differentiating communication materials for patients with lower educational attainment to reduce ambiguity aversion to medical treatments. This may involve tailoring communication to be clearer and more concise, as well as employing communication strategies to activate the reader’s personal agency to act on information on new treatments. • Patients feel averse to treatments based on ambiguous information in Lesotho. • Social endorsement from a trusted individual did not influence this attitude. • Counseling for new treatments can be tailored for patients with lower education.