Master of Science / Journalism and Mass Communications / Curtis B. Matthews / Health communication messages have been found to have a significant positive impact on audiences. However, numerous situations exist in which the general population is exposed to information from non-credible sources. This initial exposure can often bias or impact subsequent searching for more information. Vaccinations have been considered effective as a result of the number of lives that have been saved by preventing life threatening diseases. However there is also a growing group of anti-vaccine sources. The rise of the internet has resulted in the growth of numerous unqualified anti-vaccine sources. Nearly 70% of the health information that people find on the internet is from non-credible sources. These messages often take the form of videos in which a person who makes a passionate claim about the side effects of vaccines uses personal experiences (exemplars). These exemplars are used to counter the volumes of scientific and clinical research which show the effectiveness of vaccinations (base-rate information). This study manipulates the usage of passionate and dispassionate exemplars and base-rate information by simulating a real-world situation. Passionate exemplars were the most likely to create fear in our audience. Increasing the passion of our base-rate presenters exhibited both positive and negative side effects.

This dissertation is an examination of trust in vaccine science, with a focus on ideas about vaccination outside the scientific consensus. It is grounded in empirical research, including 35 interviews and a review of publicly available documents, books, and academic articles. Theoretically, it is informed by theories in the sociology of science, social movements, and the sociology of expertise. In substantive chapters, it investigates the origins of the modern ‘anti-vaccine’ movement, the spread of the movement's ideas in different sociocultural and political contexts, and the perspectives and personal experiences of those who are part of the movement. Overall, it contributes to a growing body of literature that aims to change the conversation around vaccine hesitancy from an information-deficit problem to an issue about trust in institutions. The dissertation is organized into three main papers. The first is an analysis of a specific historic episode, namely the 1998 MMR (measles, mumps, rubella) vaccine-autism controversy. I find that institutional incentive structures unintentionally circulated misinformation about the MMR vaccine by former medical doctor Andrew Wakefield and posit the role that academic reward structures have in fostering public trust. The second paper examines vaccine hesitancy with a social movement lens, specifically focusing on the strategies used by the anti-vaccine movement to organize and frame their message. I introduce the concept of an ‘anti-scientific intellectual movement’ to understand the increasing trend of social groups opposing science as a set of institutions. The third paper is a study of the lived experiences of participants who were interviewed in 2019 about their views on vaccination and how their individual experiences and meaning-making activities impacted their trust in vaccine science. I find strong distrust in scientific institutions, a desire for open dialogue and debate, and dissatisfaction with the ‘anti-vaccine’ label which participants felt erased the nuance in their perspectives. Altogether, this dissertation makes significant contributions to ongoing discussions about the public face of science and how to effectively engage with public audiences to build trust. / Dissertation / Candidate in Philosophy