If you spend any time talking to those who oppose vaccines, you will likely hear them cite the Vaccine Adverse Event Reporting System (VAERS), vaccine package inserts, and the national Vaccine Injury Compensation Program (VICP) as evidence that vaccines are dangerous. These three arguments are extremely prevalent among anti-vaccers, and many well-intentioned parents are duped by them. In many ways, this is entirely understandable. I think that most parents who refuse to vaccinate are truly trying to do what is best for their children, and I understand why parents are concerned when they see a long list of symptoms that have been reported after a vaccine. However, if you really want to do what is best for your child, then it is important to fact check, use good sources, and use those sources in the way that they are intended to be used. It is on that last point that these three arguments fail. Indeed, none of these three sources are intended to provide evidence of causation, and anyone who cites them as evidence that vaccines are dangerous is misusing them. As I will explain, the fact that an adverse event was reported in one of these three sources does not actually indicate that vaccines caused that event; therefore, you cannot present these sources as evidence that vaccines are dangerous.
Before I talk about these three topics specifically, I want to make some very general comments about anecdotes, because that is what all three of these sources report. As I explained in detail here, anecdotes do not provide evidence of causation. Coincidences do happen, and the fact that two things occurred together does not mean that one caused the other. In fact, it is a logical fallacy to say “X happened before Y, therefore X caused Y” (in technical terms, this is a post hoc ergo propter hoc fallacy). This is especially true with very common events such as vaccines. So many children receive vaccines that, statistically, we expect there to be lots of cases where some form of injury/debility closely follows vaccination just by chance. This is a crucially important point: the fact that an adverse event followed the administration of a vaccine does not mean that the vaccine caused it. This is often difficult for people to accept because our brains are wired to see patterns, but the reality is that we often see patterns that aren’t really there.
Look, for example, at “lucky” items. Does Bob’s “lucky shirt” really help his favorite sports team win? No, obviously it doesn’t. It’s just a coincidence that the team won several games while he was wearing the shirt. Nevertheless, our brains are wired to see associations even when there aren’t actually causal relationships. Further, we are prone to confirmation biases. For example, every time that Bob’s team wins while he is wearing the shirt, his confidence in the lucky nature of his shirt will grow; whereas if the team loses while wearing the shirt, his brain will tend to downplay that or invent an excuse for why the shirt didn’t work for that particular game.
The exact same thing happens with medicines like vaccines. We are pattern recognition machines. So when we see SIDS, autism, etc. follow a vaccination, our brains latch onto that association, when the reality is that those two events might be total coincidences (just as Bob wearing his shirt and the team winning are coincidences). Further, confirmation biases can really skew things. If, for example, you suspect that a vaccine might be dangerous, it is extremely easy to find lots of cases of parents reporting an adverse event after a vaccination, and that will inevitably bolster your belief, but, because of the way that confirmation biases work, you will tend to ignore all of the times that the given event occurred without a vaccination or didn’t occur following a vaccination. As you will see, this is one of the big problems with VAERS, package inserts, and the VICP. They make it very easy to bolster an existing suspicion, but they are actually only showing you part of the story. They give your brain enough information to form a pattern, but not enough information to form an accurate pattern.
Vaccine Adverse Event Reporting System VAERS
Let’s begin with the VAERS database. This is a self-reported database of adverse events that followed vaccination. There are several very important things to note there. First, the fact that it is self-reported means that the quality of data is highly variable and often low. Anyone, regardless of medical training, background knowledge, biases, etc. can report an adverse event. So there is very little in the way of quality control on the reported information. To quote the VAERS website, “Reports vary in quality and completeness. They often lack details and sometimes can have information that contains errors.”
Self-reported databases like this are problematic for a number of reasons, not the least of which is recall bias. Our memories are imperfect and easily biased, and we tend to fixate on some events more than others. Imagine, for example, that a child becomes very ill. His/her parents will naturally want to know the cause, and events like vaccinations tend to stand out in our memories. In other words, we naturally focus on them more than on other seemingly less significant events which may actually have been very important. Thus, parents may attribute the illness to a vaccination that happened a month ago simply because they are looking for answers, and that stands out in their memories.
In addition to the problems associated with self-reporting, it is extremely important to realize that VAERS is simply a collection of events that happened after a vaccination. It is not a collection of events that were caused by a vaccination. Again, remember that the fact that event X happened before event Y does not mean that event X caused event Y. So you can’t actually use VAERS as evidence of causation. You don’t, of course, have to take my word for this, because VAERS explicitly says this. If you go to the VAERS data page, the very first sentence says the following (my emphasis):
“When evaluating data from VAERS, it is important to note that for any reported event, no cause-and-effect relationship has been established. Reports of all possible associations between vaccines and adverse events (possible side effects) are filed in VAERS. Therefore, VAERS collects data on any adverse event following vaccination, be it coincidental or truly caused by a vaccine. The report of an adverse event to VAERS is not documentation that a vaccine caused the event.”
Later on that same page they state (again my emphasis):
“A report to VAERS generally does not prove that the identified vaccine(s) caused the adverse event described. It only confirms that the reported event occurred sometime after vaccine was given. No proof that the event was caused by the vaccine is required in order for VAERS to accept the report. VAERS accepts all reports without judging whether the event was caused by the vaccine.”
It doesn’t get any clearer than that. According to the VAERS website itself, the database does not prove that vaccines were responsible, it does not establish causation, and it is not documentation that vaccines are dangerous. So you absolutely cannot use this database as evidence that vaccines are harmful and are causing injuries. That is a gross misuse of this database.
What this database is useful for, and what it is intended for, is to provide an “early warning system” that identifies potential problems that should be studied. In other words, scientists look at databases like this to identify topics that need to be examined more closely. Then, they do large, controlled studies on those topics to determine whether or not the vaccine is actually causing the problem. I cannot overstate the importance of this point. The database simply identifies topics to be studied, and the actual studies determine whether or not a causal relationship exists. You need to know the rate of the event in question with and without vaccines, while controlling all of the other variables before you can reach a causal conclusion, and VAERS simply does not provide those data.
Finally, it is worth mentioning that a number of anti-vaccine scientists (particularly the Geiers) have tried to mine VAERS for evidence that vaccines are dangerous, but that is an extremely problematic statistical design. Being systematic and carefully controlling potential confounding factors is essential in science, but because of the completely unsystematic and totally uncontrolled nature of databases like VAERS, it is really hard to get reliable, high-quality data out of them. In other words, these databases do not contain the controls that are necessary for assessing causal relationships or even for accurately assessing trends over time. As such, you should be extremely skeptical of any paper that is basing conclusions on VAERS.
Vaccine package inserts
Another anti-vaccine favorite is the package inserts. The Skeptical Raptor wrote an excellent and detailed post on these, so I will just hit the highlights. These package inserts contain a variety of information about the vaccine, but the part that anti-vaccers focus on is the list of adverse reactions. These contain a wide range of ailments, including things like autism. The situation is, however, very similar to the reports in VAERS.
The lists of adverse reactions in vaccine inserts simply contain any adverse events that were reported during clinical trials for the vaccine (sometimes they also include post-approval reports). To be fair, these are usually limited to events that were severe or were reported multiple times. In other words, the point of these lists is to provide information that is potentially clinically useful, thus they include any reactions which were either severe enough to be potentially concerning, or common enough that it is plausible that the vaccine was causing them. They do not, however, actually demonstrate that they vaccine caused the reaction (with the exception of reactions for which properly controlled trials were conducted). Just like the VAERs database, these lists are simply intended to guide doctors and future researchers, rather than providing evidence of causation.
In other words, if several of the test subjects in a clinical trial became ill and vomited several days after receiving the vaccine, then nausea would be reported as an adverse reaction, but that clearly does not mean that the vaccine causes nausea. It is entirely possible (even likely) that, during the trials, some patients would become sick from things that are completely unrelated to the vaccine. Similarly, if patients experienced headaches, those would get reported regardless of whether or not the vaccine actually caused the headaches. So, just as with VAERs, the fact that something is on the vaccine insert does not mean that the vaccine causes it.
Also, as with VAERs, you don’t have to take my word for this, because the package inserts often explicitly state that they do not provide evidence of causation. For example, here is an excerpt from the Tripedia DTaP vaccine insert (this is an insert that is often cited for including autism in the list; my emphasis).
“Events were included in this list because of the seriousness or frequency of reporting. Because these events are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequencies or to establish a causal relationship to components of Tripedia vaccine.”
Also, note the fact that the adverse reactions were self-reported. This, once again, makes it very difficult to establish causation or accurate rates.
Finally, even if all of the events were causally related, you need to know their rate with and without vaccines before that information is useful. Everything has risks (including the decision not to vaccinate), so you always have to weigh the risks associated with taking an action against the risks associated with not taking that action. In other words, if a vaccine has a deadly side effect, but that side effect only occurs in 1 in every ten million injections, then the risks associated with avoiding the vaccine will far outweigh the risks associated with taking the vaccine. So you absolutely have to know the rates before you can make a properly informed decision. Simply showing that X causes Y is not sufficient.
National Vaccine Injury Compensation Program (VICP)
Finally, we arrive at the VICP. This is a no-fault system that was set up to compensate families for injuries caused by vaccines, and anti-vaccers often cite its mere existence as evidence that vaccines are dangerous. There are several important points that need to be made here. First, vaccines do have side effects (as do all real medications). No one denies that, but the side effects are generally minor, and serious side effects are quite rare. So, the benefits outweigh the risks. Thus, simply showing that vaccine-injuries exist does not prove that vaccines are dangerous. As I explained in the package inserts section, you need to take the rate of side effects into account when assessing risk.
Second, the program was established because pharmaceutical companies were being bogged down with lawsuits, and there was concern that the vaccine supply would be jeopardized. Therefore, since settling is often cheaper than fighting a lawsuit, the government set up this program as a means of protecting the vaccine supply, and they set it up to be very generous to the public. As the Skeptical Raptor explained in detail in this post, the requirements for getting money from the VICP are greatly relaxed compared to traditional courts. Applications don’t have to prove that the vaccine manufacturer was at fault, nor do they have to prove that the vaccine caused the damage. Rather, they generally just have to show that it is plausible that the vaccine caused the damage, and this can often be accomplished by something as simple as having an “expert” testify and say that it is plausible (i.e., you often don’t need actual studies showing that vaccines can cause the side effect in question). In other words, the system is set up to give the benefit of doubt to the applicant. So the fact that someone received money from the VICP is not an admission that the vaccine actually caused the injury (i.e., this is a very different situation from being found guilty or liable in a traditional court).
Finally, and perhaps most importantly, even in situations where a particular court claimed that a vaccine actually caused an injury, that still does not count as valid scientific evidence, because lawyers, judges, etc. can easily reach incorrect conclusions. In other words, the fact that a particular judge awarded money for a claim of vaccine injury only shows that the judge in question thought that the vaccine caused the injury. It does not, however, indicate that the scientific evidence shows that the vaccine caused the injury (i.e., this argument is a form of the appeal to authority fallacy).
In short, neither VAERS, nor the package inserts, nor the VICP provide evidence that vaccines are dangerous. VAERS and package inserts simply show adverse events that were reported following a vaccination, but they do not actually demonstrate that the vaccine caused the event in question. Indeed, both sources even state that the fact that an adverse event was included in them does not mean that the vaccine actually causes that event. Similarly, the VICP is a no-fault system, and applicants do not have to demonstrate that a vaccine caused the injury for which they are seeking compensation. Rather, they simply have to provide some evidence (such as expert testimony) that it is plausible that a vaccine caused the injury. Thus, none of these sources provide evidence of causation, so none of them can be used as evidence against vaccines. To be clear, vaccines do have side effects, as do essentially all real medications; however, to actually know which side effects are caused by vaccines, you need properly controlled studies, not glorified anecdotes. Further, even when a causal relationship has been demonstrated, you also have to consider the rate at which the injury occurs. Every decision has risks (including the decision not to vaccinate), and although vaccines do have complications, serious side effects are extremely rare and the benefits are extremely high. Therefore, the benefits of vaccinating outweigh the risks, and vaccinating your children will give them the best chance of living long, healthy lives.
- 5 reasons why anecdotes are totally worthless
- 15 Common Anti-Vaccine Arguments and Why They are a Load of Crap
- 100 bad arguments against vaccines
- Vaccines and autism: A thorough review of the evidence
- Vaccines don’t give lifelong immunity, but they are still better than natural immunity
- Yes, vaccines did save us from disease: a graphic analysis
Dorit Rubinstein Reiss. 2015. National vaccine injury compensation program facts. Skepticalraptor.com. Accessed 25-July-2016.
VAERS Data. Vaccine Adverse Event Reporting System. vaers.hhs.gov/data/index. Accessed 25-July-2016.
Skeptical Raptor. 2016. Argument by vaccine package inserts — debunking myths. Skepticalraptor.com. Accessed 25-July-2016,
Sanofi Pasteur. 2005. Diptheria and Tetanus Toxoids and Acellular Pertussis Vaccine Absorbed. Tripedia. Fda.gov. Accessed 25-July-2016.
Thanks – excellent article!
I think another point to take away from the VICP is that, even if 100% of all awards were 100% based on scientific evidence (and they aren’t, although scientific evidence does play a part in the program), injury awards are still so incredibly rare. I was looking up the stats last week for the MMR and MMRV. From 2006-2014, there was 1 compensated award for about 840,000 doses.
As a parent, looking at statistics like that actually makes me feel *more positive* about vaccinating, especially knowing that just measles does a lot more damage.
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Another excellent post! thank you, shared widely.
Thank you for this!