Category: Vaccine Side Effects

How Often Do Severe Events Occur After Vaccines?

Most of us understand that vaccine reactions are usually mild. While severe events can occur after vaccines, they are very rare.

“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

Unfortunately, being worried about severe reactions sometimes scares parents away from vaccinating and protecting their kids.

How Often Do Severe Events Occur After Vaccines?

Hopefully, realizing just how rare these severe reactions are will help more parents understand that all of the benefits of vaccines (very big) truly do outweigh the risks (very small).

How often do severe events occur after MMR vaccines?
How often do severe events occur after MMR vaccines?

So how often do these events occur?

Are there any statistics?

Using the MMR vaccine information statement as an example, we see that it lists the following severe events:

  • deafness – which is so rare to be associated with MMR that it is hard to tell whether they are caused by the vaccine
  • long-term seizures, coma, or lowered consciousness – which is so rare to be associated with MMR that it is hard to tell whether they are caused by the vaccine
  • brain damage – which is so rare to be associated with MMR that it is hard to tell whether they are caused by the vaccine
  • severe allergic reaction – which occurs in less than 1 out of a million doses
  • serious injury or death – which is so rare to be associated with MMR that it is hard to tell whether they are caused by the vaccine

Wait.

Why can’t we tell if these problems are caused by the vaccine?

In some cases, the association is based on a few case reports.

“With respect to the recent claims of deaths caused by MMR vaccine, drawing broad cause and effect conclusions between vaccination and deaths based on spontaneous reports to VAERS, some of which might be anecdotal or second hand, is not a scientifically valid practice. In fact, a review of the VAERS data reveals that many of the death reports for MMR vaccine involved children with serious preexisting medical conditions or were likely unrelated to vaccination (e.g., accidents). These complete VAERS reports and any accompanying medical records, autopsy reports and death certificates have been reviewed in depth by FDA and CDC physicians and no concerning patterns have emerged that would suggest a causal relationship with the MMR vaccine and death.”

Miller et al on Deaths following vaccination: What does the evidence show?

Mostly though, these type of severe events just occur so rarely after getting vaccinated.

“As for vaccines causing death, again so few deaths can plausibly be attributed to vaccines that it is hard to assess the risk statistically.”

WHO on Six common misconceptions about immunization

At a rate of less than 1 in a million doses, it gets hard to know if something was really caused by the vaccine or if it was just a coincidence, as you don’t have a lot of cases to compare with each other.

Still, it should be reassuring that even if they were caused by the vaccine, these serious events are extremely rare.

Vaccines are safe, with few risks.

More on How Often Severe Events Occur After Vaccines

Anaphylaxis After Vaccines

Anaphylaxis after vaccines is a well known side effect, but just how common is it?

Anaphylaxis After Vaccines

Since it is listed as a possible reaction to nearly all vaccines and it can be life-threatening, anaphylaxis must be fairly common, right?

“Vaccine providers should be familiar with identifying immediate-type allergic reactions, including anaphylaxis, and be competent in treating these events at the time of vaccine administration. Providers should also have a plan in place to contact emergency medical services immediately in the event of a severe acute vaccine reaction.”

Preventing and Managing Adverse Reactions

After all, pediatricians even get warned to have a plan in place and to be prepared to treat children just in case they develop anaphylaxis after getting their vaccines.

Your pediatrician will likely have an EpiPen in the office in case your child has an anaplylactic reaction after his vaccines.
Epi Is Readily Available to Treat Most Kids with Anaphylaxis After Vaccines

Still, most probably have never had to.

“Any medication can cause a severe allergic reaction. Such reactions to a vaccine are estimated at about 1 in a million doses, and would happen within a few minutes to a few hours after the vaccination.”

Possible Side-effects from Vaccines

And that’s because anaphylaxis after vaccines is very rare.

Anaphylaxis After Vaccines is Rarely Fatal

And suprisingly, it is even more rare for these cases to be fatal!

“All 30 patients with anaphylaxis survived (9 reports specified anaphylaxis, and we classified another 21 as probable cases, based on compatible clinical features, including respiratory and skin symptoms within 4 hours after vaccination). In half of 22 detailed reports, symptoms developed within 15 minutes after vaccination.”

Wise et al on Postlicensure Safety Surveillance for Varicella Vaccine

But that study just looked at the chicken pox vaccine and used VAERS, so we have to be concerned about under-reporting, right? Well, not necessarily. Under-reporting likely isn’t a big problem for serious reactions.

Anyway, that’s not the only study…

“We identified 33 confirmed vaccine-triggered anaphylaxis cases that occurred after 25,173,965 vaccine doses. The rate of anaphylaxis was 1.31 (95% CI, 0.90-1.84) per million vaccine doses.”

McNeill et al on Risk of anaphylaxis after vaccination in children and adults

The McNeill study used the Vaccine Safety Datalink, which unlike VAERS, is not a passive reporting system. So there is no concern about underreporting.

And like the Wise study, there were no deaths among these vaccine-triggered anaphylaxis cases.

“Fatalities from vaccine-induced anaphylaxis are exceedingly rare.”

Adverse reactions to vaccines practice parameter 2012 update

Similarly, a study in the UK found rare reports of anaphylaxis after vaccines in children and all those children made a full recovery.

Parents should understand that while anaphylaxis is a known side effect to getting a vaccine, it is extremely rare, and can usually be treated. This once again reinforces that vaccines are safe!

More on Anaphylaxis After Vaccines

Can Vaccines Cause Rhabdomyolysis?

The urine is dark because of myoglobinuria secondary to muscle break down. Hemoglobinuria, from blood, is the other thing that makes urine dark.
The urine is dark because of myoglobinuria secondary to muscle break down. Hemoglobinuria, from blood, is the other thing that makes urine dark. Photo Kumar et al (CC BY-NC-SA 3.0 US).

You have probably never heard of rhabdomyolysis.

Children with rhabdomyolysis have severe muscle pain, muscle weakness, and dark urine.

It is classically caused by exercising too much (really overdoing it or exercising a lot more or a lot longer than you typically do) and damaging your muscles, leading to a breakdown of muscle cells and the release of creatine kinase, which in addition to muscle symptoms, can lead to kidney failure.

In addition to exercise, rhabdomyolysis can be caused by seizures, drugs, toxins, insect stings, snake bites, metabolic disorders, infections (viral myositis), and trauma.

“The most common causes of pediatric rhabdomyolysis were viral myositis (38%), trauma (26%), and connective tissue disease (5%).”

Mannix et al on Acute Pediatric Rhabdomyolysis: Causes and Rates of Renal Failure

Keep in mind that rhabdomyolysis is rare. You won’t confuse the aches and pains that most kids get, and which often get blamed on growing pains, with rhabdomyolysis. Although younger kids don’t always have dark urine when they have rhabdo, the pain and weakness is severe. Seek immediate medical attention if you think that your child might have rhabdomyolysis.

Can Vaccines Cause Rhabdomyolysis?

It is well known that rhabdomyolysis can be caused by infections.

“Rhabdomyolysis has been reported to be associated with a variety of viral infections, including influenza, [15,16] Coxsackie virus, human immunodeficiency virus (HIV), echovirus and cytomegalovirus [17]. In our series, the definite viral infection was identified in 5 patients (influenza type B in 4, Coxsackie A10 in 1)”

Chen et al on Clinical spectrum of rhabdomyolysis presented to pediatric emergency department

So if a natural influenza virus infection can cause rhabdomyolysis, does that mean that the flu vaccine can too? What about other vaccines?

Not necessarily, but there are a few case reports that associate vaccines with rhabdomyolysis.

“Influenza A infection has been described as a major viral cause of infection-induced rhabdomyolysis, but to date, only one reported case was described as having been induced by influenza vaccine.”

Callado et al on Rhabdomyolysis secondary to influenza A H1N1 vaccine resulting in acute kidney injury.

In several of the reports, patients already had chronic medical problems for which they were being treated. Still, no signal was found to suggest that the flu vaccine is a problem for these patients.

It is important to note that reports of post-vaccination rhabdomyolysis in healthy people are even rarer.

So while it is could be possible that vaccines are rarely associated with rhabdomyolysis, we know that many infections, including many vaccine-preventable diseases, are a more common cause.

Don’t skip or delay a vaccine because you might have heard that vaccines cause rhabdomyolysis.

Vaccines are safe, with few risks, and are obviously necessary.

More on Vaccines and Rhabdomyolysis

Is Ocular Palsy a Vaccine Injury?

Now why would anyone think that an ocular palsy could be caused by vaccines?

There is no real evidence that a cranial nerve six palsy, which causes strabismus or esotropia, is a common vaccine injury, even though Dr. Bob focused on it recently.

Is Ocular Palsy a Vaccine Injury?

What is Dr. Bob’s evidence?

A vaccine injury story from a vaccine hesitant mom who was giving her child one vaccine at a time and who became cross-eyed five days after getting the MMR vaccine.

“It is an absolutely, 100% well known vaccine reaction to live virus vaccines as you eventually discovered, it’s called ocular palsy.”

Bob Sears

Is that true?

Not exactly.

It is true that there are a handful of case reports of toddlers developing a cranial nerve six palsy after a live virus vaccine, but that doesn’t make it an “absolutely, 100% well-known vaccine reaction.”

Why not?

The story Dr. Bob tells could be published as a case report. But that wouldn’t be proof that it was caused by the MMR vaccine, as other causes weren’t ruled out, and it is easy to overlook that the child had just had a double ear infection.

“Benign isolated 6th nerve palsy of childhood is rare, and recurrences are rarer. By definition, it is not due to a threatening cause, such as an underlying intracranial lesion, and recovery is expected. This condition typically occurs following viral illnesses, infections, and immunization involving attenuated live vaccinations. In general, prognosis for benign recurrent 6th nerve palsy is excellent, and majority of patients recover full muscle function.”

Gonçalves et al on Benign Recurrent Sixth Nerve Palsy in a Child

Could the child that Dr. Bob talks about have had a viral infection causing their sixth nerve palsy?

Sure. The child even had a double ear infection the previous month.

Considering that in most of the case reports, the children developed symptoms later, between 7 or 21 days to as late as 6 weeks to 6 months after their vaccine, then the previous ear infection starts to look like a more likely cause, not the MMR vaccine.

“A previously healthy four-year-old girl was presented to our emergency room with complaints of binocular horizontal diplopia of sudden onset and strabismus.”

Gonçalves et al on Benign Recurrent Sixth Nerve Palsy in a Child

What’s different about the four-year-old girl discussed above and the child Dr. Bob talks about?

“One week prior to the event, the child had a history of fever and productive cough, and she was under treatment with amoxicillin. There was no history of live attenuated vaccine administration in the previous days.”

Gonçalves et al on Benign Recurrent Sixth Nerve Palsy in a Child

This child wasn’t recently vaccinated.

There are also case reports of children developing recurrent 6th nerve palsy without any obvious trigger – no immunization and no recent infection.

And cases from the 1950s and 60s and earlier, before we had an MMR vaccine.

“This syndrome is not a new entity, and experienced clinicians recall cases in which the combination of only fever and VI nerve palsy cautioned them against other diagnostic measures. Sir Charles Symonds, in a discussion recorded in the proceedings of the Royal Society of Medicine, makes reference to his observations of patients in whom VI nerve palsy followed febrile illness and was of no consequence. In the same discussion he also mentions instances in which VI nerve palsy followed otitis media, and yet there was no pain and little constitutional disturbance. The palsy he considered to be the result of an aseptic thrombosis of the inferior petrosal sinus, adjacent to the VI nerve as it passes through Dorello’s canal.”

Knox et al on Benign VI Nerve Palsies in Children

Also consider that if a live attenuated vaccine is causing such a vaccine injury, then wouldn’t you expect kids with natural measles infections to develop these 6th nerve palsies at equal, or more likely, greater rates.

What about those case reports from the 1950s and 60s and earlier? No, those early case reports weren’t about kids with measles.

The bottom line is that if you want to consider this type of ocular palsy a vaccine injury, you should also explore the possibility that it was caused by an infection or by chance. And the only folks who would say 100% that these incidents are a vaccine injury, when there is just as much, if not more, evidence saying they aren’t, are those who think that everything is a vaccine injury

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