Other articles offer more unusual theories. One warns of the imminent development of a “Supervaccine” containing “raw DNA from 40 different kinds of bacteria and viruses that will be given to all newborn infants and timed [sic] released into the body throughout life.”7
Concerns about civil liberties were mentioned on 5 of the sites reviewed. One site11 claims that “the system will monitor, intimidate, harass and punish conscientious parents, their children and health care providers if they do not conform with every government recommended vaccination health care policy.” This site offers instructions on how to remove children from a state vaccine registry.
Nearly all of the Web sites reviewed make an effort to appear unbiased about vaccination. This is often reflected in the names chosen for the organizations and Web sites and also in many of their mission statements. For example: “Our mission: to help the public make informed and intelligent decisions about childhood and adult vaccines.”12 Several Web sites are very skillful in maintaining ambiguity on their home page: for example, “Vaccination. Does it work? Is it safe? Investigate so that you can make an informed choice.”13 Typically, moving to the next page exposes the reader to an alarming list of adverse effects.
Many of these Web sites list contraindications to vaccination. In addition to those that are generally accepted, several sites list conditions that are not normally recognized as contraindications. Some of the advice offered to parents is directly at odds with accepted medical practice (Table).
Several pages provide advice and resources for parents wishing to avoid childhood vaccination. “How to Legally Avoid School Immunizations”14 reviews religious and philosophical exemptions to immunization and strategies for obtaining them. Instructions are provided to help parents write letters to exempt their children from vaccination.
Discussion
Antivaccination Web sites are not difficult to find. Parents surfing the Web for information on vaccination are very likely to encounter one or more of these sites.
Most of the sites reviewed in this study use several arguments to make a case against vaccination. Fifteen of the 26 sites reviewed appear to be associated with groups or individuals advocating the use of alternative medicine to treat or prevent infectious disease. The association between anti-immunization attitudes and promoters of unconventional therapies has been noted previously.15 One study from the United Kingdom reported that the use of homeopathy by the family was the most common reason for parental refusal of childhood immunizations.16 A study carried out in the United States reported that one third of a national sample of chiropractors opposed immunization.17
With the rise in popularity of alternative and complementary medicine among the general public, more individuals may be advised to avoid immunizations by providers of alternative care. Although there is no direct evidence that increased use of complementary medicine results in a decline in immunization rates, Australia, which has the lowest childhood immunization rate in the developed world,18 also has the highest reported use of complementary medicine in the general population.19
Other organizations appear to be contributing to the antivaccination debate as well, each focusing on its own agenda, such as civil liberties or conspiracy theories. In this respect, the modern antivaccination movement appears to share many characteristics with these types of movements in the past. What is new is the availability of this information to many individuals who may not be able to assess its reliability. Another difference is the ease with which the new medium allows small geographically isolated groups to network.
Although the actual number of proponents of the antivaccination movement is unknown, the efforts of a dedicated minority coupled with declining public awareness of the seriousness of vaccine preventable diseases may set the stage for the erosion of an important cornerstone of public health. Physicians should be aware of this growing movement and consider offering anticipatory guidance to parents about questionable material on the Internet. Research clarifying the relationship between alternative health care beliefs and immunization practices is urgently needed.