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The Flu Shot: How Dangerous, How Effective, Should You Get It?

Louise Hendon | November 13
should you get the flu shot?

“I’d NEVER get the flu shot – it’s got mercury in it.”

That was my coworker’s reaction after I told her that I had just gotten my flu shot (which I had told her as a passing “I should say something to make conversation” statement.)

This definitely was not the response I was expecting, and it suddenly invoked strong feelings within me:

  • Fear. Had I just willingly allowed someone to inject mercury into my veins?
  • Anger. Why is she trying to scare me with her sensationalist claims again?
  • Quite a lot of confusion. So what is this flu shot all about anyway – does it even work?

Let’s just say that those feeling did not lead to the most productive of conversations. However, what it did leave me was a feeling that I had to get to the bottom of this.

Are flu shots dangerous or am I just defending my sense of pride for having gone and gotten a flu shot without examining all the facts? What does the flu shot protect against – did I just waste all that time for something that won’t even protect me from the flu? And should I get the flu shot in the future?

Are Flu Shots Dangerous?

There are no proven significant side-effects from flu vaccines. The most common side effects from the flu shot are aches and fatigue.

However, what we hear on the news is about scary rare illnesses that have been linked to the flu shot.

For example, it is often mentioned that Guillain–Barré syndrome (GBS) is caused by flu shots. This is an illness that can last a few weeks but rarely causes death or permanent damage, and you can get this disease regardless of whether you get vaccinated or not.

So should I be scared of getting GBS after my flu shot?

A 2013 study on GBS found that there is a 1 in a million chance of developing the syndrome after receiving the flu vaccine (and developing the illness rarely led to anything permanent.)

Does that mean the flu shot has no scary side effects?

Unfortunately, the exact risk of serious side effects from the flu shot may never be known. Most of the studies for flu vaccinations have been funded by the drug companies, which often leads to the “file drawer” effect (whereby studies showing a result contrary to the drug company’s goals are placed into a dark and never-to-be-opened file drawer.) So there is a good chance that even the side effects we currently know about are underestimated.

There’s also the possibility that each year’s new vaccination (e.g., a new “quadrivalent” vaccine is being introduced in the U.S. this year) could have certain side effects that were not present in past vaccines.

But that’s just the side effects traceable to the flu vaccine. What about the ingredients in the vaccine that could be harmful to us?

The Ingredients in Flu Vaccines Aren’t That Scary

I’m careful about what I eat because I don’t want to put toxins into my body. It therefore makes sense to not inject random chemicals into my body. However, while there are some suspect chemicals in the flu shot, they are present in very small amounts (especially when compared to how much you are constantly exposed to those chemicals in daily life.)

For example, mercury and formaldehyde could both be present in your flu shot. Sounds nasty, right?

Mercury Compounds
The multi-dose shot contains thimerosal (a preservative that can break down into mercury compounds). The single-dose shots and the nasal sprays do not contain thimerosal.

Just the word “mercury” sends alerts up to my brain, but thimerosal is really completely different from the mercury that we are typically afraid of. In our body, thimerosal can break down into ethylmercury, which exits the body pretty quickly and hasn’t been found to cause any significant harm to us (e.g., a 2004 study found no link between thimerosal and autism in children.)

But if you want to be extra cautious, then go for the single-dose or the nasal spray.

Very small amounts of formaldehyde are used in most brands of flu vaccines to inactivate the virus. In each dose, there’s around 5 µg to 25 µg of formaldehyde. Compare that amount to 8600 µg to 13200 µg of formaldehyde present in a pear naturally!

(If you want to know more about what goes into the flu vaccine, this website has all the details: ponents-Influenza.htm.)

But what about for kids? The CDC also recommends that kids (everyone over six months of age) get vaccinated.

The Verdict is Unclear for Children

A 2012 Cochrane report had some interesting conclusions about the flu vaccines for children.

They found that flu vaccines for children under two years of age “are not significantly more efficacious than placebo.” However, they also concluded that the vaccines did seem to work for children over two years of age.

Another important conclusion that they drew was that: “It was not possible to analyse the safety of vaccines from the studies due to the lack of standardisation in the information given, but very little information was found on the safety of inactivated vaccines, the most commonly used vaccine in young children.”

One argument based on these conclusions is that kids under two years of age shouldn’t be getting the vaccination when it doesn’t protect them and when we don’t even know the side effects of the vaccination.

It’s a tough choice either way when you’re a parent (you want to protect your child but not expose them to unnecessary risk.) Unfortunately, I don’t have a good answer here.

However, it’s not just for kids that the vaccine isn’t effective – it’s also not that effective for adults either!

flu shot is not very effective

The Flu Vaccination is Not Very Effective

Every year I’ve gotten the flu vaccine, I’ve expected it to be a magic pill for preventing the flu. I go through the inconvenience of the shot, and viola, I avoid the flu for that year. Sadly, it seems that very few people get any benefit from the flu vaccine.

According to a report by the Center for Infectious Disease Research and Policy at the University of Minnesota, “influenza vaccine protection is markedly lower than for most routinely recommended vaccines and is suboptimal.”

To quantify the flu vaccine’s ineffectiveness, Tom Jefferson from the Cochrane Vaccines Field stated that: “you need to vaccinate between 33 and 99 people to prevent one case of flu, depending on the match between the vaccine and the circulating strains of the virus.”

But they claim that the flu shot is over 50% effective at preventing the flu!

What that 50% means is that if 1% of people who got vaccinated still got the flu but 2% of people who didn’t get vaccinated got the flu, there is a 50% reduction in relative risk, but the absolute risk reduction is just 1%.

I know, it’s really confusing even for me with multiple physics degrees – this quick example might help.

If there are only 100 people in the world and none of them got vaccinated, then around two of them would get the flu each year (this is the real statistics for getting the flu on a basic level.) However, if we vaccinate all 100 people in the world, then only one of them would now get the flu each year. So by vaccinating all 100 people, we saved one1 person from getting the flu (1% of all people in the world.) But half (or 50%) of the people that would have gotten the flu didn’t get the flu due to the vaccine.

So, after all that, the bottom line is simply that if you do get the vaccination, you can still get the flu so don’t hope for too much. However, the vaccine does work (there is a reduction in the number of people getting the flu!)

Should You Get the Flu Shot?

Last year I got the flu shot because it was offered in my office – it took a few minutes out of my day to walk up the stairs and receive a shot (no waiting time, no cost to me, and I assumed it would be effective at lowering my chances of getting the flu.)

This year, I didn’t, partly because I realized the flu shot isn’t all that effective. But realistically, there are several other reasons for my decision. For instance, I don’t work in that office any more, and so I would have to go somewhere to get it. I’d also have to see if it’s covered by my new, cheaper health insurance, and I’d have to take time to plan where to go and when to go.

Having lived sickness-free for a while now, I am also less fearful of getting the flu or being as debilitated by it. I know that if I feel any symptoms, I will immediately get more sleep, cut down on my exercise, and eat more nutrient-dense foods.

So, I can’t give you a definitive answer as to whether or not you should get the flu shot, but what I can tell you is that whether or not you get the flu shot, you should still take some preventative measures to keep yourself healthy and sickness-free during the cold and flu season. This article has some ideas for how to do that.

Are you going to get the flu shot?

So, what did you decide to do this year? Flu shot or no?

There is a comprehensive terms and conditions page (here) that covers this entire website and every post/article/recipe/statement etc. within, and you can always access that page from the bottom of every page. But here is a short version.
NOTICE AND DISCLAIMER: Information contained in this article is not intended to and shall not convey or recommend any medical or nutritional advice or course of action. Any course of action you undertake should be discussed with your doctor or other licensed medical professional. All opinions expressed in this article are based solely on personal experiences and research. I am NOT a licensed doctor, dietitian, or nutritionist.

John S. - November 14

Louise it is so nice to see scientific literacy and investigative critical thinking in a primal food blog! I adore your food posts but it is very nice to see you covering topics like this. I like your review of the evidence however I think that one point you may not have touched on enough is that flu shots (like all other vaccines) cannot be thought of as an individual decision otherwise the impact seems negligible. Vaccines must be considered from the perspective of herd immunity. Although the benefits seem negligible on an individual level when you reach certain thresholds the illness can be kept at bay and provides less fit members of society (immune compromised people, children and elderly) protection. The flu (or whooping cough or measles) may seem like something you can tough through but if you get it or carry it (you can transmit without showing symptoms) to one of these groups the results can be deadly.
I am in no way trying to diminish your post I just wanted to point this out. Thank you for the wonderful blog and thought provoking topic!

    Louise Hendon - November 14

    Thanks John – great point. I think it also raises the issue of whether we’d be doing everyone else a favor if we all ate well and got sick less 🙂

Kate M - November 15

Thanks for this post Louise! I love that you did your research!! There is SO MUCH misinformation out there in the world – especially when it comes to vaccines. It’s difficult waters to navigate at times for a lot of people. It’s great that you make it so clear and concise in this post! Nice work.

Jen - November 18

I like that you bring up the points that most tests are funded by pharmaceutical companies, and that perhaps not all symptoms are recognized or recorded by them. I have a good friend whose baby went into seizures 20min. after getting his first vaccine. They told her it was a coincidence. He went on to have other complications and continuing seizures for the rest of his childhood. After 7 years of trying to get the health authority to recognize his reactions, she gave up. They refused to acknowledge it, or include his case among any data collected. So, I wonder how many others have been ignored.

    Louise Hendon - November 18

    Thanks Jen – I’m so sorry for your friend and her son. The way research is done in the science community is most definitely not designed to figure things out but to prove someone right. There are a lot of unknowns sadly.

Diane - November 18

One also has to remember that the flu shot, and all vaccine shots, are introduced into the body in an unnatural way. They bypass the natural immune system – and I wonder how that effects our bodies and the reactions. Also, while one flu shot may not be so scary, it is scary when you see all the recommended vaccines they want our children to get. And the ingredients and culturing of those vaxes. Vaccines may not be the “gun” to all the evils of kids these days, but I think the absolute number of them is definitely a “bullet.” And once again, all of these vaccines have never been tested together to see what happens…

Linda Sand - November 18

When I was ten years old I got such a severe case of the flu I missed an entire month of school. I was so sick my classmates wrote me get well letters. Trust me, you don’t want to be the one person who should have had a flu shot.

Kirsten - November 18

Why anyone would ever allow all this unnecessary poison into their precious bodies, not to mention their childrens is beyond me. We’ve been brainwashed about vaccines big time. And after having research big time and knowing the true history about vaccines and their horrible ingredients NO vaccines are allowed here. Unfortunately most people still believe that vaccines have saved millions of lives, have eradicated polio ect. – it is simply not true, all these illnesses have been in natural decline before the vaccines were introduced. When the truth comes out – and it will – people will realize that vaccines are a crime against humanity. They do not save lives – they cause tons of cronic and neurological diseases and death. People are generally more sick than ever. NO thank you. D3 and othe great supplements and healthy food is the best prevention and if a cold and the flu comes along take it – don’t fight it – it is the body’s natural way of detoxing.

Kirsten - November 18

… and by the way herd immunity regarding vaccines is a fallacy, an unproved theory – herd immunity only exits in nature.

Julie M. - March 7

Louise, thanks for your thoughtful analysis of the issue, but I have to draw a completely different conclusion. If there’s no proven benefit, especially for people who are eating a Paleo diet and supplementing with Vitamin D, and the medication carries ANY risk at all, then the choice has to be, “No, thanks.” That just makes sense.

I get very upset that they push especially the flu shot on kids, pregnant women, immune compromised and elderly people who takes lots of medications with potentially unrecognized interactions with the flu shot. In fact, there is not adequate safety testing for them. They test for ten days. That’s it! One study showed that elderly people getting flu shots four years in a row had significantly higher rates of Alzheime’s disease. There’s no long term safety testing at all, but children and fetuses are at genuine risk from the chemicals because of their lower body mass. And, as you point out, the flu shot is reformulated year, so the “safety testing” basically resets every year, too. There are what are known as “hot batches” where the vaccine is bad or contaminated. (Not that you can sue anyone over that — vaccine products are 100% indemnified by the government, even in cases where it’s PROVEN to be defective! How insane is that??) Also, it’s long been speculated that some individuals can get an extraordinary dose of mercury, if the caregiver neglects to SHAKE THE MULTI-DOSE VIAL. Then all best are off. Mercury is a very heavy element, a known neurotoxin, and it settles to the bottom. Now that you can get jabbed at any given pharmacy, at schools, at your office, etc., and the training and quality of health care providers administering the shots is now potentially sketchy, the possibility of getting a toxic dose from a multi-dose vial is higher than ever. I’m not taking that chance. The less-risky pediatric doses are limited in their availability each year, so lots of kids get the regular, mercury-containing doses even though mercury has been removed from the rest of their shots for safety.

Then there’s Flu Mist. Flu Mist is a live virus, which has its own set of risks and is pretty much guaranteed to transmit the disease to those around you for up to 20 days, per Table 5 in the product insert. So much for herd “immunity!” LOL More like “herd exposure.” I laugh, but I think it’s really obnoxious that people think they’re protecting the health of others by getting the shot, meanwhile they’re swilling the very same germs to everyone around them.

Also, there are more side effects reported to VAERS for the flu shot than for any other vaccine product. They’re made on the fly and it’s a crap-shoot as to whether or not they even get the right strains for that year. As for herd immunity and the flu shot, I think the flu shot is actually meant to introduce various flus into the population on a rotating basis, because the #1 side effect is the flu! HALF the people I talk to who get the flu shot invariably get the flu shortly there after. Most people get a runny nose, which is all you near to spread the live virus. How does that makes any sense? Unless the shot is meant to build the immunity of the whole population, whether everyone gets the shot or not.

Also, it makes me nervous that they keep including the H1N1 virus in the quadravalent. They make this up as they go. There is no safety testing to see how it affects people to get the same strength shot every season for the same damned strain of the flu. Maybe that’s WHY after four years of the H1N1 Boogyman, instead of more and more of the population being inoculated successfully for it, assuming not everyone gets the shot every year, we’re apparently seeing an increase in the disease and in the severity of it this year, or so they say. Makes no sense that it’s getting worse when the odds are strong that more people have been inoculated, if you assume the vaccine even works.

In any case, if you’re eating bone broths on a weekly basis and taking Vitamin D, which has been shown in some studies to be AS EFFECTIVE as the flu shot, you’re most likely going to be among the 98 people out of 100 who don’t get the flu! And your chances of side effects from the vaccine immediately drop to 0%.

J.D. - March 10

Thank you for this article! It seems well-balanced and well thought out. I’ve gone back and forth about the flu shot and vaccines in general. I don’t get to sit on the fence anymore, unfortunately. The decision is made for me, since I work in healthcare. Even if I am healthy, wash my hands religiously, and wash my white coat and stethoscope, I am required to have all vaccinations. I could not have gone to school and could not have gained employment without them. In many hospitals, a decline of a vaccination comes with huge stigma, sometimes a reduction in pay, and at the very least, being forced to wear a mask while at work (even if the employee works in billing!). I’m not sure how that’s legal, since the HIPAA laws should make your healthcare decisions private..but some employment contracts include a clause about the required vaccines. It’s touchy.

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