Content and design attributes of antivaccination web sites.

Context: Individuals searching the Internet for vaccine information may find antivaccination Web sites. Few published studies have systematically evaluated these sites.

Objectives: To examine antivaccination Web site attributes and to delineate the specific claims and concerns expressed by antivaccination groups.

Design And Setting: In late 2000, using a metasearch program that incorporates 10 other search engines, we reviewed and analyzed 772 links to find 12 Web sites that promulgated antivaccination information. Analyzing links from these 12 sites yielded another 10 sites, producing a total of 22 sites for study. Using a standardized form, 2 authors (R.M.W., L.K.S.) systematically evaluated these sites based on specific content and design attributes.

Main Outcome Measures: Presence or absence of 11 Web site content attributes (antivaccination claims) and 10 Web site design attributes.

Results: The most commonly found content claims were that vaccines cause idiopathic illness (100% of sites), vaccines erode immunity (95%), adverse vaccine reactions are underreported (95%), and vaccination policy is motivated by profit (91%). The most common design attributes were the presence of links to other antivaccination sites (100%of sites), information for legally avoiding immunizations (64%), and the use of emotionally charged stories of children who had allegedly been killed or harmed by vaccines (55%).

Conclusion: Antivaccination Web sites express a range of concerns related to vaccine safety and varying levels of distrust in medicine. The sites rely heavily on emotional appeal to convey their message.