Draft date: August 5, 2002. For private use only. Please do not cite until formally published. An abbreviated version of this article is scheduled to be published in the Medical Sentinel, a peer-reviewed medical journal.
Abstract. The so-called antivaccination movement uses the internet to disseminate information that is contrary to official recommendations. Unofficial web sites have been criticized for being emotional, factually incorrect, unduly influential, and dangerous. A review shows that the criticisms are wildly exaggerated, and that dissent from official medical policy is serving a very constructive role. If anything, I argue that we need more dissent, not less.
The internet is a wonderful source of medical information.  It varies from the latest and highest quality medical research, to kooks promoting dangerous and fraudulent quack remedies. Several recent studies warn that there are many readily accessible non-government medical web sites that have information that does not agree with the official government web sites. 
This article focuses on popular information about vaccination on the internet. In many areas of medicine there is a split between mainstream and alternative medicine, and the gap seems especially sharp in the case of vaccination.
In the United States, the Centers for Disease Control and Prevention (CDC) publishes an official schedule for childhood vaccination.  There are very specific recommendations for when, how, and whether to vaccinate. Nearly all government and physician groups have closed ranks behind this schedule, and do not equivocate about whether the schedule is best. Enforcement of vaccination is left up to the states, but most children get vaccines according to schedule and are required to present proof of vaccination on entry to school. Criticism of vaccine policy is almost entirely confined to internet sites.
Vaccination web sites generally fall into two camps -- those that endorse the official vaccine schedule and those that do not. Of those that do, there are many high-quality sites. The most comprehensive site is maintained by the CDC , where you can find the Weekly Mortality and Morbidity Weekly Report, and assorted articles and facts on various diseases and vaccines.
The web sites that do not endorse the official vaccine schedule vary in quality. Some have information that is outdated, paranoid, or factually incorrect. For the most part, these sites are not really opposed to vaccination. They promote parents making an informed choice, and usually believe that the medical authorities are not giving a balanced view of the risks and benefits of vaccines, for various reasons.
The medical establishment likes to promote the myth that the internet is dangerous because of medical information that has not been approved by the medical authorities. A case in point is two recent studies which lamented the availability of so-called antivaccination web sites.  These studies surveyed vaccination information on the web, and found dozens of vaccination sites that did not endorse the official vaccine schedule and provided an assortment of contrary arguments.
The tone of these studies is somewhat alarmist because they suggest that antivaccination web sites are outside the control of the medical authorities and are winning the hearts and minds of mothers by using methods of persuasion that pediatricians cannot easily rebut. The studies don't really consider the accuracy of the web sites, or compare them to official vaccination web sites. Instead they are more like reconnaissance reports on what the enemy is doing.
These two studies are grossly inaccurate in their most central claims. The main point of the Wolfe et al study in JAMA  was to describe 22 web sites  that were chosen on the basis of containing "content specifically opposing vaccination for human infants or children." In fact few, if any, sites express such an opinion. I contacted several of the webmasters, and they all adamantly objected to this characterization. They say they want to promote informed choice, safer vaccines, better public accountability, etc.
One might say that a web site must be opposed to vaccination if it has a page suggesting that MMR might cause autism, because no one wants autism. But that is just not true. Ralph Nader once made a name for himself by attacking General Motors, but he was not opposed to the automobile. He just wanted safer cars. Likewise, the vaccine critics just want safer and better drugs and medical practices.
JAMA did not publish the list of 22 web sites. I got the list  privately from one of the authors. If JAMA had published the list, then anyone with a web browser could see that the sites had been misrepresented. It is also ironic that JAMA does not put the full article freely on the web, and the article complains about the quality of what is freely available on the web.
The Davies et al article  about finding "antivaccination activists" with internet search engines was also false in some of its central assertions. The abstract says that 43% of hits for "vaccination" and "immunisation" (or "immunization") were antivaccination. But the paper's own Table 1 says it was 43% for vaccination and 6% for immunisation (or immunization). So the combined percentage is only 24% by the paper's own data.
The Davies paper also complains that the first 10 hits on Google  for vaccination are all antivaccination web sites. But that's not true today, I doubt that it was ever true. The first Google link is to Category: Health - Child Health - Immunizations, a directory listing of 23 web sites with a balanced set of facts and opinions. For example, it includes government and pediatrician sites promoting vaccines.
The next Google link is to the Australian Vaccination Network.  This site is listed as one of the 100 antivaccination web sites, but it is not really opposed to vaccination at all. It merely provides information about vaccine risks and advocates allowing people to make an informed choice. Sites like this provide a useful service to parents making a vaccination decision.
At least the journal (owned by BMJ) published the list of 100 sites on its web site. A number of the links in the appendix are broken, so I posted a corrected list. 
Some of the Davies criticisms don't make much sense. The paper complains that 27% of the antivaccination sites use names that (falsely) imply some sort of official status, and yet it also says that 99% have an "us versus them" appeal where the site is pitted against the official authorities. I don't see how a site can pretend to be official and unofficial at the same time.
The paper also attacks sites for not doing what they claim. It says that 33% of the sites claim to present both sides of the vaccination debate, but only 15% actually do. It also says that 31% of the sites have links to government and health agency sites promoting vaccination. Apparently many vaccine sites give the arguments for vaccines by having links to those arguments on CDC.gov and elsewhere. I really don't see how a site can be faulted for using the CDC as representative of official vaccine policy. It is a bit like using the Republican party platform as representative of the Republican political position.
It might have been instructive for these studies to compare the so-called antivaccination web sites to the official vaccination web sites.  The unofficial sites warn of various risks of adverse effects, but so do the official sites. The difference is largely one of emphasis. The unofficial sites tend to rely heavily on anecdotal scare stories or emotional arguments, but some official sites also have scare stories to promote their point of view. 
While only a third of the Davies antivaccination sites had links to so-called provaccination sites, none of the major official sites have links to any sites that criticize the official vaccine schedule.
In the interest of full disclosure, I'll note that while both AAPS  and myself  have some materials on the web which criticize official vaccine policy, our sites were not named in the recent studies. I am happy to be excluded because I am not opposed to vaccines, and my online comments only address certain aspects of vaccines. The same is true about some other so-called antivaccination sites, so I don't know why AAPS and I were excluded.
With a number of thorough and reliable official vaccination web sites available, one can ask whether the unofficial sites are offering anything useful at all, or are they cluttering up the web with dubious information that distracts parents from getting what they really need.
Here are some examples of useful information that the unofficial sites provide.
Even those who get fully vaccinated according to the schedule often find it useful to get a contrasting view before making a medical decision. It is like getting a second opinion before surgery, or talking to a Honda dealer before buying a Ford automobile.
Some people think that there is a dangerous antivaccination movement. The Davies study opened:
Campaigns by those opposed to immunisation have been followed by falling immunisation rates and outbreaks of vaccine preventable disease. The internet has provided antivaccinationists with unprecedented opportunities for exposure.
It is hard to see how anyone could be concerned about it in the US, as the vaccination rates are at an all-time high.  People have accepted an ever-increasing schedule of vaccines -- the schedule now requires all babies to get 16 to 20 injections against 11 diseases within the first 18 months of life.  Rates are kept high by the fact that proof of vaccination is required for school. But even in states like Colorado where any parent can get an exemption by stating that the vaccine is against her personal beliefs, the total exemptor rate is only about 2%.  Furthermore, all of the powerful interests support these high rates -- the federal and state government, the schools, the pediatricians, and the drug companies. There is no money on the other side.
To support the idea that antivaccination movements can be dangerous, there have been several studies purported to document how such movements have caused great harm in the past. The Lancet published a study by Gangarosa et al in 1998  about how anti-vaccine movements succeeded in several countries in sabotaging public confidence in vaccines, resulting in a huge drop in the vaccination rate, a big increase in the corresponding disease, and ultimately reinstatement of high vaccination rates once everybody recognized the disaster. The obvious moral to the story is that the antivaccination movement must be stopped before it causes a lot of unnecessary suffering among children.
Two of the main examples in the Gangarosa study involve Sweden and Japan in the 1970s. Both countries used the DTP vaccine, like most of the developed world. DTP protects against diptheria, tetanus, and pertussis. Pertussis, also known as whooping cough, is the main reason for getting the vaccine, but the pertussis part of the vaccine is also the part that causes the most adverse effects.
Manufacture of the DTP vaccine in Sweden was defective, and the vaccine was ineffective.  Eventually, critics complained about the high risks and low benefits of DTP, and by 1975, "Swedish pediatricians had lost confidence in the vaccine", according to the Gangarosa study. Pertussis rates rose.
Meanwhile, there was a big public controversy in Japan over serious adverse effects that were associated with DTP. Because of public pressure, the government dropped the pertussis vaccine, and offered just the DT vaccine. Pertussis rates rose. To halt the rise, Japan introduced the acellular DTP (now called DTaP) vaccine 1981. It was much safer than DTP, and the public accepted it. Pertussis rates dropped back down.
No doubt the vaccine critics in Sweden and Japan greatly irritated the medical authorities by undermining public support. But Sweden and Japan ended up much better off for their efforts. Sweden was using a inferior DTP vaccine while its neighbors in Europe were using a much more effective vaccine. Better testing should have caught the problem, but the it was not caught until it was so obvious that the general public understood that the Swedish DTP vaccine was unsatisfactory.
In Japan, the public protests persuaded the authorities to switch to the much safer DTaP vaccine. The US has mandatory vaccination, and the vaccine makers and medical authorities are less responsive to consumer demands. The US FDA did not even approve the DTaP vaccine until 1996,  and DTP has only recently been phased out. If the US did not have mandatory vaccination, or if the US had a more active antivaccination movement, maybe we could have gotten the safer DTaP vaccine in 1981 when Japan got it.
Other changes in US vaccine policy have occurred much too slowly. When the oral and injected polio vaccines (OPV and IPV) were introduced 40 years ago, there was sharp debate about which was better, and the OPV was adopted even though it can cause polio in the vaccinated child and in others. When polio was eradicated from the US around 1980, IPV should have been the vaccine of choice. But only recently has the CDC switched to IPV.
Vaccination critics also complained for years that several vaccines contain thimerosal which could cause mercury toxicity. The FDA and CDC stubbornly refused to do anything until it was actually shown that the mercury levels exceeded federal guidelines if a baby gets all the scheduled vaccine. Only in the last couple of years have the vaccine makers removed most of the mercury from the vaccines.
The creation of the Vaccine Adverse Event Reporting System (VAERS) and the Vaccine Injury Compensation Program  were largely as a result of lobbying by vaccine critics. So was the mandatory issuance of Vaccine Information Statements (VIS) to parents. 
The history of medicine, and in vaccination in particular, is full of examples of official mistakes that were only corrected as a result of public dissent. Unofficial vaccine information web sites provide balance to parents who need to make a medical decision, and fill a much-needed political role in criticizing official policymakers.
The government vaccine policy decision-making process has many flaws.  The USA authorities can rightly brag about many wonderful accomplishments, including the eradication of smallpox, polio, and measles from the country. But their decisions are not perfect and their recommendations are not necessarily the best. Even the AMA suggests that the states should not blindly follow the federal recommendations. [JAMA ED]
There are a number of current controversies related to vaccination. For example:
While vaccination critics have succeeded in getting the authorities to switch to safer vaccines in some cases, the process has been slow and incomplete. The federal advisory committees are still being run like a private club of drug company insiders. Marginal and poorly tested vaccines regularly get added to the official mandates with little public opposition. Vital vaccine data and policy rationales are withheld from the public. The CDC and the drug companies lobby the states to pass stricter and more coercive vaccination laws. There is an imbalance of power and influence, and it favors the proponents of aggressive vaccination policies. We need more vaccination critics so that the issues will be debated in a more open and scientific manner, and so that parents and others can make safe and informed vaccination decisions.
There is every reason to believe that unofficial vaccination web sites will continue to serve a positive and useful role in our society. Government and other official web sites would be doing a public service if they were to provide links to web sites that are critical or present other points of view.