Emerging and continuing trends in vaccine opposition website content

Context: Anti-vaccination websites appeal to persons searching the Internet for vaccine information that reinforces their predilection to avoid vaccination for themselves or their children. Few published studies have systematically examined these sites. Objectives: The aim of this study was to employ content analysis as a useful tool for examining and comparing anti-vaccination websites for recurring and changing emphases in content, design, and credibility themes since earlier anti-vaccination website content analyses were conducted. Methods: Between February and May 2010, using a commonly available search engine followed by a deep web search, 25 websites that contained anti-vaccination content were reviewed and analyzed for 24 content, 14 design, and 13 credibility attributes. Results: Although several content claims remained similar to earlier analyses, two new themes emerged: (1) the 2009 H1N1 epidemic threat was manufactured, and (2) the increasing presence of so-called expert testimony in opposing vaccination. Conclusion: Anti-vaccination websites are constantly changing in response to the trends in public health and the success of vaccination. Monitoring the changes can permit public health workers to mount programs more quickly to counter the opposition arguments. Additionally, opposition claims commonly appeal to emotions whereas the supporting claims appeal to reason. Effective vaccine support may be better served by including more emotionally compelling content. (C) 2011 Elsevier Ltd. All rights reserved.