Tag: reporting 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

Side Effects and Adverse Events Following Immunizations

Vaccines are safe, but they do have some side effects, mostly mild, and they rarely cause some serious and severe adverse reactions.

Vaccine adverse events can be reported to VAERS online or using a downloadable form.
Vaccine adverse events can be reported to VAERS online or using a downloadable form.

To help keep our vaccines safe, it is important that all “clinically important adverse events that occur after vaccination of adults and children” be reported to VAERS, not just the ones that are known to be side effects.

Wait.

Isn’t an adverse event the same as a side effect?

Adverse Events Following Immunizations

To better understand that, let’s first look at how we define an adverse event following immunization (AEFI):

“An Adverse event following immunization (AEFI) is any untoward medical occurrence which follows immunization and which does not necessarily have a causal relationship with the usage of the vaccine. The adverse event may be any unfavourable or unintended sign, abnormal laboratory finding, symptom or disease.”

Classification of AEFIs

So it should be clear that not all adverse events are actually caused by vaccines.

Many are coincidental events that simply occur after a vaccine is given.

What’s the Difference Between Side Effects and Adverse Events Following Immunizations?

Others are true vaccine reactions though, including fever, pain, fainting, and allergic reactions, etc.

“A side effect is any health problem shown by studies to be caused by a vaccine. Like any medication, vaccines can cause side effects. Usually vaccine side effects are minor (for example, a sore arm where a shot was given or a low-grade fever after a vaccine) and go away on their own within a few days.”

Understanding Side Effects and Adverse Events

These are the reactions that we call side effects or adverse reactions of the vaccine.

Still, just because a sign or symptom can be a side effect of a vaccine doesn’t mean that it always will be.

“A vaccine reaction is an individual’s response to the inherent properties of the vaccine, even when the vaccine has been prepared, handled and administered correctly.”

Vaccine reactions – WHO Vaccine Safety Basics

Here are some other definitions:

  • adverse event – Medical occurrence temporally associated with the use of a medicinal product, but not necessarily causally related.
  • adverse reaction/side effect – A response to a drug which is noxious and unintended, and which occurs at doses normally used in man for the prophylaxis, diagnosis, or therapy of disease, or for the modifications of physiological function.
  • unexpected adverse reaction – Not consistent with applicable product information or characteristics of drug.
  • severe adverse event or reaction – are rarely life-threatening and usually do not result in long-term problems
  • serious adverse event or reaction – Any untoward medical occurrence that at any dose is life-threatening, results in death, requires inpatient hospitalization or prolongation of existing hospitalization, or results in persistent of significant disability or incapacity

Does understanding those definitions make it easier to see why you should be skeptical when folks try to scare you with VAERS reports and data from package inserts?

“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.”

Guide to Interpreting VAERS Data

They both can include reports about adverse events, not just side effects. So they both include events that can very well be coincidental, and not caused by a vaccine.

So when doing your research about vaccines, focus on real side effects, or things that are known to be caused by vaccines. You will find that most vaccine side effects are mild and that more serious or severe side effects are very rare.

More on Side Effects and Adverse Events

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

What Are the Side Effects of the Flu Vaccine?

Like other vaccines, flu vaccines can have side effects.

Fortunately, most of those side effects are mild.

What Are the Side Effects of the Flu Vaccine?

Not surprisingly, a lot of things that get blamed as being caused by flu vaccines are not actually side effects.

Did you actually get the flu in the days or weeks after your flu vaccine?

That’s not a side effect of your flu vaccine. Neither the inactivated flu shot, nor the attenuated FluMist can actually cause a flu infection.

Did you get a little sore at the site where you got your flu shot?

That’s a common side effect to getting a flu shot.

So is having some redness and swelling at the site, all of which begin soon after getting the shot and go away in a few days. You can also get a headache, fever, nausea, and muscle aches or signs and symptoms of an allergic reaction.

Do you have a runny nose or a cough? Side effects of the nasal spray flu vaccine can include a few days of runny nose, wheezing, headache, vomiting, muscle aches, fever, sore throat and cough.

Again, a bad cough and cold after a flu shot isn’t a side effect of the vaccine though.

Remember, correlation does not imply causation.

If you found out you were pregnant shortly after getting a flu shot, you wouldn’t think they were associated, would you?

What about narcolepsy?

“An increased risk of narcolepsy was found following vaccination with Pandemrix, a monovalent 2009 H1N1 influenza vaccine that was used in several European countries during the H1N1 influenza pandemic.”

Narcolepsy Following Pandemrix Influenza Vaccination in Europe

Although the focus has been on the Pandemrix flu vaccine as a trigger for narcolepsy in some countries (the vaccine wasn’t used in the United States), interestingly, several countries that weren’t using the vaccine also saw a spike in narcolepsy cases as the 2009 H1N1 pandemic hit.

Doctors and pharmacies rarely give away flu shots for free. They might not charge a copay sometimes because they are getting paid by your insurance company!
Doctors and pharmacies rarely give away flu shots for free. They might not charge a copay sometimes because they are getting paid by your insurance company!

What about all of the reports of severe reactions and deaths after getting a flu shot that you might hear about? In addition to vaccine injury stories, those reports are to VAERS and typically are not causally related to getting a vaccine.

Why are there so many reports to VAERS and the NVICP about flu vaccines? Since 2006, over 1.6 trillion doses of flu vaccine have been distributed in the United States, which equals about the total of all other vaccines we use.

What Are the Side Effects of This Year’s Flu Shot

Even when folks understand that flu vaccines don’t typically cause serious side effects, the question always comes up whether or not this year’s flu shot is causing more side effects than usual.

That’s actually not unreasonable, even when you consider that the biggest change in most flu vaccines from year to year is the strain of flu viruses they include, and not any of the other ingredients.

In addition to the Pandemrix flu vaccine, in 2010, the use of one brand of flu vaccines in Australia was suspended because they were causing more side effects (fever and febrile seizures) in young children than expected.

“The studies flesh out preliminary findings from CSL in June 2012, which said that the manufacturing process retained more virus component than that of other manufacturers and that the 2010 virus components triggered an excessive immune response in some young kids.”

CSL studies shed light on 2010 flu vaccine seizures

So are there any more side effects this year?

No, there is no evidence of increased side effects from this year’s flu vaccines

More on Flu Vaccine Side Effects