266. The Emerging Landscape of Anti-Vaccination Sentiment On Facebook

Abstract

High levels of vaccination have been essential at curbing the rate of vaccine-preventable diseases and early deaths, yet an increasing number of individuals refuse vaccines for themselves or their children. Previous research suggests that anti-vaccination rhetoric on social media may serve to facilitate anti-vaccination behavior. However, the vast majority of this work has focused on Twitter or content on public social media pages (e.g. public Facebook groups). Therefore, this study aimed to characterize individuals known to publicly post anti-vaccination content on Facebook. Our dataset consisted of 197 individuals on Facebook who posted distinctly anti-vaccination comments on a prominent local pediatric clinic’s Facebook page. These comments were in response to a 90-second video that promoted the HPV vaccine as an anti-cancer vaccine, as recommended by the National Cancer Institute. In order to increase feasibility of quantitative double-coding and qualitative assessment, we obtained a random subsample of 25% of the 795 individuals who posted these comments, resulting in our dataset of 197 individuals. For each individual, we systematically analyzed publicly available content on their Facebook page over a two-year period (2015-2017) using quantitative coding of sociodemographic characteristics and anti-vaccination posts, social network analysis (SNA), and an in-depth qualitative analysis. Of the 197 individuals, 89% identified as female. There were 36 states and 8 countries listed across individuals that identified their location (n=136). Of the 116 individuals whose profile contained publicly viewable anti-vaccination posts during the time frame under analysis, the most frequent anti-vaccination topics were “educational material,” such as testimony from health professionals against vaccines (73%); “censorship and cover up,” alleging cover-up by organizations of adverse vaccine reactions (71%); and “vaccines cause idiopathic illnesses,” such as rashes or seizures (69%). For SNA, a two-mode network was constructed, and there were 1068 connections between individuals and topics. Modularity analysis found anti-vaccination topics and people tend to cluster into 4 sub-groups, each with a different primary reason for opposing vaccines: (1) emphasis on liberty, (2) focus on naturalness, (3) vaccine safety, and (4) conspiracy theories. Qualitative analysis revealed that many of these individuals use language that is consistent with the characteristics of science denialism. Individuals also post about other themes (e.g. alternative medicine, anti-genetically modified food) in ways that cluster into the subgroups identified through SNA. Examining the content of Facebook profiles known to post anti-vaccination content provides insight into the characteristics and beliefs of these individuals. Individuals who commented on the Facebook page of a pediatric practice located in a single U.S. city were based in locations around the globe, suggesting those against vaccination may be connecting in new ways via social media. Moreover, although the anti-vaccine movement has long been tied to autism, current arguments against vaccination are diverse, with individuals and anti-vaccination topics clustering into distinct subgroups. These findings suggest the need for health professionals to develop more effective interventions that reflect the beliefs of each subgroup to counter the anti-vaccination movement on social media.