BACKGROUND:
Experts project that by 2005, one billion people will be online. The U.S. has over 160 million Internet users and 80% of these individuals use the Internet to research health information. Although many websites provide accurate immunization information, many more disseminate misinformation, causing patients and parents to doubt the safety and efficacy of vaccination.

OBJECTIVE:
First, to examine popular vaccine-critical websites and catagorize the types of misinformation they propound. Second, to examine the possible hidden motivations of these website developers. Third, to provide links to reliable websites and Internet evaluation resources for health providers and their patients.

METHOD:
Several dozen of the most popular vaccine-critical websites were examined using basic website evaluation criteria for credibility and content. Google Internet searches uncovered additional information about the organizations and individuals associated with these sites.

RESULT:
The types of misinformation found included: appeals to emotions, false conclusions from true statements, straw man arguments, unsubstantiated statements, hidden profit motivation, appeals to distrust of government and industry, appeals to distrust of medical profession, dubious connections, and conspiracy theories. Hidden motivations included self-serving vaccine-critical statements from chiropractors and alternative medicine practitioners, sites selling commercial products, and attorneys offering their services to those “damaged by vaccines.”

CONCLUSION:
An individual looking for immunization information on the Internet is likely to encounter much misinformation. None of the vaccine-critical websites pass the basic standards of credibility and content as detailed by the Global Advisory Committee on Vaccine Safety (www.who.int/vaccine_safety/good_vs_sites/en) Those providing immunization services need to know what their patients might be reading on the Internet and be able to provide answers and alternative resources.

LEARNING OBJECTIVES:
1) Understand the types of misinformation patients are likely to encounter on the Internet, 2) Be able to provide patients with reliable sources of immunization information, 3) Be able to provide patients with tools to evaluate health websites.