What makes anti-vaccine websites persuasive? A content analysis of techniques used by anti-vaccine websites to engender anti-vaccine sentiment

Anti-vaccine sentiment can be extremely resistant to change, making it difficult to promote childhood vaccines. Thus, there is a need for effective strategies to communicate the benefits of vaccination to vaccine hesitant parents. Understanding how anti-vaccine advocates successfully persuade parents against vaccinating their children can provide insight into communication tactics that could be incorporated into vaccine promotion efforts. The internet is an important source of vaccine information for many parents, and plays a role informing vaccine hesitancy. To understand what might make anti-vaccine websites so convincing, we used persuasion theory as a lens to examine what information was being presented, and the persuasive tactics being used to communicate the information. We conducted a content analysis of 480 anti-vaccine websites. Four trained coders coded sites for the content of the vaccine information being presented, types of persuasive tactics used, and values and lifestyle norms associated with anti-vaccine advocacy. Anti-vaccine websites contain a considerable amount of misinformation, most commonly that vaccines are dangerous, cause autism and brain injury. Websites used both scientific evidence and anecdotes to support these claims. Values such as choice, freedom, and individuality were linked to anti-vaccine beliefs. The most commonly co-promoted behaviors included the use of alternative medicine and homeopathy, and eating a healthy or organic diet. Anti-vaccine websites use a battery of effective persuasive techniques to forward their agenda. The use of similar persuasive techniques and tapping into parents’ values and lifestyles are potentially useful strategies for vaccine promotion communication.