Table 2.
Types of information on vaccine-critical websites
| Type of Information |
Websites With This Attribute (%) |
Interrater Reliability (Kappa)* |
| DESCRIPTIVE CONTENT | ||
| Vaccine Criticism | ||
| Links to other sites critical of vaccines | 80 | 0.718 |
| Information for legally avoiding immunizations | 47 | 0.719 |
| Information on reporting adverse events | 35 | 0.661 |
| Vaccine critical books, tapes, compact discs for purchase from site | 33 | 0.738 |
| Email listserv or chat room (eg, to discuss vaccine dangers) | 28 | 0.558 |
| Solicitations for contributions for website support or anti-vaccine cause or organization | 21 | 0.654 |
| Links to attorneys | 20 | 0.800 |
| Disease Risk/Vaccine Safety | ||
| Specific illnesses are attributed to vaccination, (eg, multiple sclerosis, autism, asthma, sudden infant death syndrome) | 91 | 0.529 |
| Vaccines contain contaminants, mercury, or there are “hot lots” of vaccine that cause adverse events | 83 | 0.687 |
| Vaccines afford only temporary protection and/or outbreaks occur despite vaccination | 79 | 0.688 |
| Diseases prevented by vaccines have declined, are not contagious, or are relatively mild illnesses | 74 | 0.702 |
| Physicians under-report adverse reactions | 62 | 0.677 |
| Alternative Medicine | ||
| Encourages “back to nature” alternatives to vaccination such as homeopathy, vitamins/minerals/supplements, chiropractic services | 67 | 0.565 |
| Conventional medicine is wrong; some physicians disagree with vaccination | 63 | 0.531 |
| Physicians are misinformed about vaccines | 58 | 0.606 |
| Sells herbal and/or homeopathic products | 16 | 0.575 |
| RHETORICAL APPEAL | ||
| Emotive Appeals | ||
| Responsible parenting mandates educating oneself; parents must stand together against the establishment | 76 | 0.540 |
| Pictures and/or stories of children allegedly harmed by vaccinations | 37 | 0.573 |
| Pictures or diagrams of needles | 22 | 0.522 |
| Ethical Allegations | ||
| Safety and efficacy information is false; cover-up and conspiracy about safety is alleged | 76 | 0.528 |
| Civil liberties are violated by taking away parental choice | 70 | 0.666 |
| Conflict of interest exists between vaccine manufacturers and doctors or policy makers | 66 | 0.630 |
| Vaccine mandates infringe on parental rights; totalitarianism is suggested | 63 | 0.561 |
| Immorality argument—vaccines are grown on cell lines derived from abortions; universal vaccination is a form of utilitarianism which sacrifices a few for the benefit of many | 46 | 0.555 |
| Government protects doctors and manufacturers from liability for harm caused by vaccines | 33 | 0.601 |
P < .001 for kappa for each attribute