Antivaccination activists on the world wide web

Aims: To determine the likelihood of finding an antivaccination site on the world wide web and to characterise their explicit claims and rhetorical appeals. Methods: Using "vaccination" and "immunisation", examining the first 10 sites displayed on seven leading search engines. Detailed examination of content of 100 antivaccination sites found on Google. Results: 43% of websites were antivaccination (all of the first 10 on Google). Main rhetorical appeals involve themes of the scientific veracity of antivaccination argument; rapport with parents seeking to protect their children from harm; and alleged collusion between doctors, the pharmaceutical industry, and government to deny vaccine harm. Conclusions: There is a high probability that parents will encounter elaborate antivaccination material on the world wide web. Factual refutational strategies alone are unlikely to counter the highly rhetorical appeals that shape these sites.