For example, while it might sound like there have been a lot of adverse drug reaction reports for the DTaP vaccine, with 179,447 reports in VigiAccess, since those are worldwide reports since 1968, it is likely among many billions of doses of vaccines being given.
Most importantly though, as with VAERS, “The reports in VigiBase result from suspicions of a relationship between a drug and a reaction. No causal relation has been confirmed.”
So how do you put the numbers from VigiBase and VigiAccess in context?
If you consider that reports and safety signals from VigiBase, VigiMatch, VigiRank, and other tools used by the Uppsala Monitoring Centre continue to find that vaccines are safe, then to put the DTaP numbers in context, they help us know that vaccines are being well monitored for safety.
And since we know that these diseases haven’t disappeared, any further context, if you need it, would be that since vaccines are safe and necessary, then you should get yourself and your family vaccinated and protected.
Kawasaki disease is rare and there is a good chance that you have never even heard of it, even though the first case was diagnosed in 1961.
Kids with this condition are typically irritable and can develop high fever, swollen glands in their neck, red eyes, red, cracked lips, red, swollen hands and feet, and a rash.
If you have heard of it, there is a good chance it is because anti-vaccine folks are using Kawasaki disease to scare you away from vaccinating and protecting your kids. Lately, talk about Kawasaki disease and the meningococcal B vaccines have been going around.
What Causes Kawasaki Disease?
Kawasaki disease is a type of vasculitis.
Kids who develop Kawasaki disease, who are typically under age 5 years, develop inflammation of their blood vessels, which leads to many of the symptoms and complications we see.
What causes this inflammation?
“Evidence suggests that Kawasaki disease may be linked to a yet-to-be identified infectious agent, such as a virus or bacteria. However, despite intense research, no bacteria, virus, or toxin has been identified as a cause of the disease.”
AAP on Kawasaki disease
We don’t know.
Can Vaccines Cause Kawasaki Disease?
Because the cause of Kawasaki disease is unknown, that leads some folks to think that it could be vaccines.
That vaccine clinical trial data sometimes finds a higher, although not statistically significant risk for Kawasaki disease, gets some of those folks thinking about it even more, except they don’t seem to think about the fact that the risk is never statistically significant.
But aren’t there case reports of kids getting Kawasaki disease after getting a hepatitis A, yellow fever, hepatitis B, or flu vaccine?
Yes, but getting a case report published about one patient who you think got Kawasaki disease soon after getting a vaccine isn’t strong evidence that it wasn’t a coincidence.
“Childhood vaccinations’ studied did not increase the risk of Kawasaki disease; conversely, vaccination was associated with a transient decrease in Kawasaki disease incidence. Verifying and understanding this potential protective effect could yield clues to the underlying etiology of Kawasaki disease.”
Abrams et al. on Childhood vaccines and Kawasaki disease, Vaccine Safety Datalink, 1996-2006.
And not surprisingly, several studies have shown that there isn’t any extra risk for Kawasaki disease after routine vaccines.
One even showed that getting vaccinated could be protective! Another benefit of vaccines and another reason you shouldn’t skip or delay your child’s immunizations.
What to Know About Vaccines and Kawasaki Disease
While anti-vaccine folks often list Kawasaki disease among their vaccine-induced diseases, several studies have shown that vaccines are not associated with Kawasaki disease, except to maybe have a protective effective if you are fully vaccinated.
Can a child be fine one day and then die the next?
Tragically, they can.
There is even a name for it – sudden unexplained death in childhood.
Sudden Death in Children
Although 10% of deaths in children over age 12 months are classified as sudden death, most have explanations, such as asthma, epilepsy, or a heart problem (congenital malformations and arrhythmias). Unfortunately, some of these conditions, especially some infections and heart problems, aren’t discovered until after the child dies.
“Most sudden cardiac deaths that remain unexplained after necropsy are probably caused by primary cardiac arrhythmias.”
Sudden death in children and adolescents
About 16% of these sudden deaths don’t have any explanation though.
Surprisingly, these types of sudden, unexplained deaths are the 5th leading cause of death in children between the ages of 1 and 4 years. That adds up to about 400 deaths a year in the United States alone!
“…making general assumptions and drawing conclusions about vaccinations causing deaths based on spontaneous reports to VAERS – some of which might be anecdotal or second-hand – or from case reports in the media, is not a scientifically valid practice.”
Miller et al on Deaths following vaccination: What does the evidence show?
“At the present time there is not enough known about the underlying mechanisms of death in SUDC to allow prediction of which children might die suddenly and unexpectedly. Additionally, there is no way to prevent SUDC since its cause is unknown. Through research, we strive to discover the risk factors and underlying causes of SUDC that will lead to its prevention. In the meantime, optimal pediatric care recommendations, including attending well child visits, maintaining current vaccinations, and obtaining appropriate health care when clinically indicated, should be followed.”
SUDC Foundation on Frequently Asked Questions
And it’s not just SIDS. We also see a “healthy vaccinee effect” in older kids, who have lower mortality rates than the general population, which includes some folks who aren’t vaccinated.
We don’t know what causes sudden unexplained death in children, although with continued research we hopefully soon will, and can then learn to prevent them. Until then, parents should feel confident that it is not caused by the vaccines, which are safe and necessary and work to protect them from many life-threatening vaccine-preventable diseases.
What to Know About Vaccines and Sudden Unexplained Death in Children
Vaccines are not associated with sudden unexplained death in children.
More on Vaccines and Sudden Unexplained Death in Children
It is mostly because they think that anything bad that happens after someone is vaccinated, even if it is weeks or months later, must have been caused by the vaccine.
“Differentiation between coincidence and causality is of utmost importance in this respect. This is not always easy, especially when an event is rare and background rates are not available.”
Heininger on A risk-benefit analysis of vaccination
Of course, this discounts that fact that most people have a basic risk, often called the background rate, for developing most of these very same conditions, and they can just coincide with getting vaccinated.
Put more simply, the “reaction” would have happened whether or not they had been vaccinated.
“…when a number of well-controlled studies were conducted during the 1980s, the investigators found, nearly unanimously, that the number of SIDS deaths temporally associated with DTP vaccination was within the range expected to occur by chance. In other words, the SIDS deaths would have occurred even if no vaccinations had been given.”
WHO on Six Common Misconceptions About Immunization
That doesn’t mean that everything automatically gets blamed on coincidence though.
Is It a Vaccine Reaction?
When trying to determine if a child has had a vaccine reaction, experts typically go through a series of questions, looking at the evidence for and against :
How soon after the vaccine was given did the reaction occur? Was it minutes, hours, days, weeks, months, or years later?
Is there any evidence that something else could have caused the reaction?
Is there a known causal relation between the reaction and the vaccine?
Is there evidence that the vaccine does not have a causal association with the reaction?
Do any lab tests support the idea that it was a vaccine reaction?
Why is it important to consider these and other questions?
Because most of us are very good at jumping to conclusions, are quick to place blame, and like to know the reasons for why things happen.
We don’t like to think that things are just caused by coincidence.
Post hoc ergo propter hoc (after this, therefore, because of this).
We are especially good at linking events and often automatically assume that one thing caused another simply because it occurred afterwards.
It is incident to physicians, I am afraid, beyond all other men, to mistake subsequence for consequence.
Dr Samuel Johnson
But we also know that correlation does not imply causation. And because of the great benefits of vaccines, it is important to find strong evidence for a correlation before we blame vaccines for a reaction.
Too often though, the opposite happens. Despite strong evidence against a correlation, parents and some pediatricians still blame vaccines for many things, from SIDS and encephalitis to autism.
Background Rates vs Vaccine Reactions
Although anti-vaccine folks are always calling for vaccinated vs unvaccinated studies to further prove that vaccines are indeed safe, much of that work is already done by looking at the observed rate of possible reactions and comparing them to the background rate of reactions and conditions.
We often know how many people are expected to develop certain conditions, from seizures and type 1 diabetes mellitus to acute transverse myelitis and juvenile and rheumatoid arthritis.
“On the basis of the reviewed data, if a cohort of 10 million individuals was vaccinated in the UK, 21.5 cases of Guillain-Barré syndrome and 5.75 cases of sudden death would be expected to occur within 6 weeks of vaccination as coincident background cases. In female vaccinees in the USA, 86.3 cases of optic neuritis per 10 million population would be expected within 6 weeks of vaccination. 397 per 1 million vaccinated pregnant women would be predicted to have a spontaneous abortion within 1 day of vaccination.”
Black et al on Importance of background rates of disease in assessment of vaccine safety during mass immunisation with pandemic H1N1 influenza vaccines
Intussusception is a good example of this.
This might surprise some folks, but we diagnosed and treated kids with intussusception well before the first rotavirus vaccines were ever introduced. And then, it was only after the risk of intussusception after vaccination exceeded the background rate that experts were able to determine that there was an issue.
“Knowledge of the background incidence rates of possible adverse events is a crucial part of assessing possible vaccine safety concerns. It allows for a rapid observed vs expected analysis and helps to distinguish legitimate safety concerns from events that are temporally associated with but not necessarily caused by vaccination.”
Gadroen et al on Baseline incidence of intussusception in early childhood before rotavirus vaccine introduction, the Netherlands, January 2008 to December 2012
Fortunately, studies have never found an increased risk above the background rate for SIDS, non-febrile seizures, and other things that anti-vaccine folks often blame on vaccines. So when these things happen on the same day or one or two days after getting vaccinated, it almost certainly truly is a coincidence. It would have happened even if your child had not been vaccinated, just like we see these things happen in the days before a child was due to get their vaccines.
For example, using background incidence rates in Danish children, one study found that if you vaccinated a million children with a new flu vaccine, you could expect that naturally, after seven days, you would see:
facial nerve palsy – one case
seizures – 36 cases
multiple sclerosis – one case
type 1 diabetes – three cases
juvenile and rheumatoid arthritis – three cases
After six weeks, those numbers of course go up. In addition to 4 kids developing MS, 20 develop diabetes, 19 develop arthritis, and 218 have seizures, and there would have been at least two deaths of unknown cause.
Would you blame the flu shot for these things?
What flu shot?
This was a “hypothetical vaccine cohort” that used 30 years of data from the Danish healthcare system to figure out background rates of each condition.
“In addition, the expected number of deaths in Japan following an estimated 15 million doses of H1N1 vaccine administered would be >8000 deaths during the 20 days following vaccination, based on the crude mortality rate.”
McCarthy et al on Mortality Rates and Cause-of-Death Patterns in a Vaccinated Population
Looking at background rates is especially helpful when folks report about vaccine deaths.
Using the Japan example that McCarthy studied, if they had looked at background rates, then all of a sudden, the 107 deaths they found after 15 million doses of H1N1 vaccine were given in 2009 would not have been so alarming. Background rates would have predicted a much, much higher number of deaths to naturally occur in that time period simply based on crude mortality rates.
Vaccines are safe and many of the things that folks think are vaccine reactions can be explained by looking at the background rates for these conditions and understanding that they would have happened anyway.
And understanding that vaccines are safe, makes getting their kids vaccinated an easy decision for most parents, as they understand that the many benefits of vaccines far outweigh any possible risks.
How Do We Know Vaccines Are Safe?
If you are on the fence about vaccines, simply saying they are safe might not be enough for you.
“Over the previous 40 years the IOM has conducted over 60 vaccine safety studies, including this comprehensive review of the immunization schedule. The IOM committee did not find any evidence of major safety concerns related to receiving on-time vaccinations according to the Recommended Immunization Schedule for children. They concluded that this should help to reassure stakeholders. Further, they noted that while the receiving on-time vaccines was not harmful, it was strongly associated with reducing vaccine-preventable diseases. ”
American Academy of Pediatrics on Vaccine Safety: Examine the Evidence
How do we really know vaccines are safe?
vaccines go through a long period of pre-licensure testing and evaluation when being developed to make sure they are safe and that they work before they are approved
You can also report possible side effects directly to vaccine manufacturers.
And like our Vaccine Safety Datalink, in addition to having a passive reporting system, like VAERS, many countries have an active vaccine safety surveillance system to make sure that their vaccines are safe:
Canada – IMPACT or Canada’s Immunization Monitoring Program ACTive that actively monitors “12 Canadian centres, which represent about 90% of all tertiary care pediatric beds in Canada” for “adverse events following immunization, vaccine failures and selected infectious diseases that are, or will be, vaccine preventable.”
A lot of this work is also done as part of the World Health Organization’s Global Vaccine Safety Initiative (GVSI). In fact, many (about 110) WHO member countries report to the VigiBase system that is actively monitored by the WHO’s Uppsala Monitoring Centre.
What to Know About Global Vaccine Side Effect Reporting Systems
Passive and active vaccine side effect reporting systems in countries around the world help to make sure that our vaccines are safe.
More on Global Vaccine Side Effect Reporting Systems
Anti-vaccine folks claim that an awful lot of things are encephalitis, from crying excessively after getting a vaccine to autism.
Although the Vaccine Information Statement for the DTaP vaccine (it was more common after the older DTP vaccine) does state that children may uncommonly have “non-stop crying, for 3 hours or more” it is not because they have brain inflammation, and the reaction “although unnerving, is otherwise benign.” It is not even a contraindication to getting another dose of DTaP or a later dose of Tdap.
What causes this non-stop crying? It is thought to be a painful local reaction. Fortunately, it does not happen as often with the newer DTaP vaccines.
And autism is not encephalitis.
“That measles infections can cause neurologic side effects on rare occasions is known, but the complication rate for vaccinations is low. After infectious measles encephalitis, risk of an autistic regression has occurred in 1/1000 to 1/10,000 cases. If the trend toward delaying vaccination continues because parents remain misinformed about the MMR, the number of children with neurologic complications of measles or rubella will increase. ”
Chez et al on Immunizations, Immunology, and Autism
Can encephalitis lead a child to have symptoms of autism?
In addition to natural measles infections, there have been reports of children developing autism after HSV encephalitis, varicella encephalitis, congenital rubella syndrome, and congenital syphilis.
But the great majority of kids with autism do not first have encephalitis. They do not have ongoing brain inflammation.
Saying that encephalitis can cause autism is not the same thing as saying that autism is encephalitis.
Do Vaccines Cause Encephalitis?
And even though encephalitis has long been a table injury for a few vaccines, the 2012 IOM report, “Adverse Effects of Vaccines: Evidence and Causality,” found inadequate evidence to be able to conclude that encephalitis was caused by vaccines.
“Follow-up investigations in that cohort and others, however, found no evidence of a real increased incidence of encephalitis following DTwP. In addition, the most recent IOM report concludes that the evidence is inadequate to accept or reject a causal relationship between diphtheria toxoid-, tetanus toxoid-, or acellular pertussis-containing vaccine and encephalitis or encephalopathy.”
Vaccinophobia and Vaccine Controversies of the 21st Century
That’s not surprising, because follow-up of children studied in the 1980s, from which the original claims about DTP and encephalitis were made, found no evidence of an increased risk of encephalitis.
What about the MMR vaccine?
Again, the IOM report found inadequate evidence, but the problem has always been that “acute encephalitis post-MMR is so rare that it has been impossible to distinguish from the background encephalitis rate of 1 in one million in immune competent hosts.”
Doesn’t the discovery of anti-N-methyl-D-aspartate (anti-NMDA) receptor encephalitis prove that vaccines cause autism?
“Anti-NMDA receptor encephalitis is a disease occurring when antibodies produced by the body’s own immune system attack NMDA receptors in the brain.”
The Anti-NMDA Receptor Encephalitis Foundation
Often associated with tumors, isolated case reports do correlate anti-NMDAR encephalitis with vaccines. There are so few cases of anti-NMDAR encephalitis though, it is hard to know what they mean, as are the reports of autism developing after anti-NMDAR encephalitis.
What to Know About Vaccines and Encephalitis
Vaccines still don’t cause autism and the latest safety studies report that vaccines probably don’t cause encephalitis, although a few are still listed as a table injury.