Waves of public resentment and fears centering on vaccination are not a modern phenomenon, but rather one that has reappeared throughout the history of this intervention . Unlike the earlier vaccination efforts against smallpox during the 1800's, where anti-vaccine propaganda was disseminated via posters and newspapers, proponents against vaccination now have numerous additional means to communicate their positions to the general public, the Internet being of particular importance [3, 4, 62, 63]. It is important to note that the growing plethora of anti-vaccine websites exist at a time where millions of people are using the Internet as a means to obtain medical information .
Studies that analyzed the content of anti-vaccine websites indicate that anti-vaccine proponents vocalize a minority of justifiable criticisms alongside a majority of manipulative information [3, 4, 8, 62, 63]. For example, many criticisms stem from ethical issues in relation to imposed vaccination and the loss of civil liberties, as well as avoiding unnecessary vaccine-risks in the absence of infection. Indeed, coercive vaccination policies do exist, such as restrictions in school enrolment for unvaccinated children , and many people view these policies as unethical. However, vaccine opponents equate most vaccination programs with severe forms of government oppression and often omit the fact that most vaccination programs involve voluntary compliance; only rarely is vaccination obligatory. Moreover, purported claims that vaccines are currently unnecessary are uncorroborated. Indeed, certain vaccine-preventable diseases are not overtly prevalent, but this does not mean that they no longer exist within society. Vaccine opponents also commonly note undisputed vaccine-ADRs, including allergic reactions, infections, and death. However, these anti-vaccine websites grossly exaggerate the incidence of such rare ADRs.
Propagandist information is another commonality shared by anti-vaccine websites [3, 4, 8, 62, 63]. While discredited by reliable scientific evidence, vaccine-opponents remain adamant that inoculation is the cause of debilitating diseases such as autism and multiple sclerosis. Others still claim that multiple vaccines can 'overload' the immune system and is the cause of allergy, and in general, vaccination is 'fundamentally unnatural'. Many sites report very emotional stories of vibrant, healthy children that succumbed to horrific illnesses or death following the administration of common childhood vaccines, but they do not demonstrate a causative link between the two events. Finally, many make claims that vaccination efforts are fraught with controversy and describe elaborate conspiracy theories that explain the 'true' motives underlying vaccination policies. Popular conspiracy theories include: assertions that vaccines are ineffective and that infections began to disappear prior to vaccination; governments and scientists are hiding evidence of the actual harms caused by vaccines; vaccine efforts are schemes to generate profits for large pharmaceutical companies; and that vaccine initiatives are means to conduct genocide.
It is unknown to what extent anti-vaccine propaganda disseminated through media outlets or the Internet is undermining public trust in vaccination. Numerous surveys suggest that it is significant. At a minimum, anti-vaccination websites are observed to influence public perceptions towards vaccination, where parents whom exempt their children from receiving common vaccines often have obtained information from such Internet sources . Furthermore, one study  demonstrated that up to half of American survey respondents refused the annual influenza vaccine due to the belief that they would develop influenza disease from the vaccine. Another American study  found that 15% of parents of young children did not want their child to receive any of the recommended childhood inoculations. Moreover, it is incorrect to assume that anti-vaccine sentiment is isolated amongst uneducated people or certain minority groups that share radical ideologies. Rather, a significant proportion of American supporters of the current anti-vaccination movement are of members of the middle class and have some level of university education . By and large, these studies suggest that anti-vaccine sentiment exists throughout society, where the unfounded fears and anxiety now associated with vaccination could constitute a form of mass-hysteria. When taken as a whole, the arguably irrational nature of vaccine hysteria should raise concerns about whether other 'vaccine-like' medical interventions may also become tarnished in the public eye, as is argued here concerning IT. Indeed, information found by this author on the Internet indicates that public vaccine-fears and vaccine-opposition have started being transposed onto IT and allergy therapeutic regimens.
Replicating website searches conducted by Kata  and Wolfe and colleagues [2, 63], and using search terms such as "anti-vaccination, vaccine, allergy, immunotherapy" in March 2010, yielded anti-vaccine websites and Internet blogs that have begun discussions questioning the safety and utility of IT. (A detailed quantification of these websites is beyond the scope of this article, but would be an interesting topic for future investigations). Many sites also confuse vaccination ADRs with IT treatments and purport manipulative and/or false information concerning IT and allergies. One notable example is blog entries  from the site, http://m.digitaljournal.com. What appears to be a blog entry from a member of the general public whose child received IT demonstrates that vaccine ADRs and related fears are being mistakenly associated with allergenic extracts--this entry relates to bacterial contamination of vaccines and the possible link with Guillain-Barré Syndrome (GBS):
"... after reading this report and reading there might have been bacterial contaminant in the H1N1 vaccine makes me wonder if there could have been bacterial contaminant in the allergy shots."
A subsequent entry on the same blog employs scientific jargon and claims that allergenic extracts contain the notorious "autism-causing" preservative, thimerosal:
"... if your son received an allergy shot from a multi dose vial, he(sic) more than likely had thimerosal in it. By weight thimerosal is 40.7% mercury. Mercury is a neurotoxin and can affect many areas of your body."
Another blog entry  from the website, http://childhealthsafety.wordpress.com, demonstrates similar convoluted and mistaken associations between vaccines and allergenic extracts (skin prick tests are clinical assays using allergenic extracts [e.g., peanut extract] in order to diagnose allergen sensitivities [e.g., peanut allergy]; the underline emphasis was added by this author):
"Vaccines are the direct cause of the food allergy epidemic. Why are the manufacturers of vaccines allowed trade secret protection for vaccine ingredients? Why is
peanut oil considered safe to inject along with aluminum
based on studies where children eat the oil or
based on the skin prick test?
IT ISN'T THE SAME!! The fatal food allergies are directly caused by vaccines!! The evidence is there."
Certain websites of supposed specialists in complementary and alternative medicine encourage patients to reject IT in favour of treatments such as homeopathy and often purport mistaken facts about IT and vaccination. Entries  within the website, http://e-holistichealth.blogspot.com, are exemplary (underline emphasis added):
(This entry compares allergenic extracts to vaccines) "Allergy shots are often called "vaccines" because (1) they are injected and (2) the intention of both is to confer immunity."
"... allergy shots must stop after 3 to 5 years and at that time the doctor has to decide whether to continue them or not. That would suggest that the cumulative effect of
getting allergy shots compromises immune function
in some way or has other side effects."
"Both allergy shots and vaccines have risks for allergic reactions, including anaphylaxis.
The risk is higher and more common with vaccines
(for obvious reasons)."
"...[IT] therapy only lessens the severity of the allergy response and creates other side effects (headaches, skin conditions, additional allergies )."
"Neither vaccination or allergy immunotherapy addresses the underlying organ weaknesses and immune system problems that make the person susceptible to infections and allergic reactions."
As a final example, the popular and notorious anti-vaccination website, Vaccination Liberation (http://www.vaclib.org), warns the public to reject allergy-vaccines and that the common aluminum salt adjuvants in allergenic extracts are of significant toxicological concern  (for an analysis of the website, Vaccination Liberation, see: ). Overall, this overview of Internet-based information indicates that mistaken associations between IT, vaccine-fears and the anti-vaccination movement are a current reality.