The Flu Vaccine Does Not Give You The Flu

The Flu Vaccine Does Not Give You The Flu

I’ll admit I was guilty of believing this myself: that getting a flu vaccine usually meant you’d feel a bit ill for a couple of days because the vaccination effectively gave you a mild dose of the flu. Turns out that’s absolute garbage.

Picture by Daniel Paquet

At The Conversation, Sydney University senior lecturer Julie Leask explains why this widespread belief is, in fact, false. And there’s a simple up-front reason for that:

It’s physically impossible for the flu vaccine to cause the flu (influenza) because the vaccines licensed for use in Australia are all inactivated. This means the viral cells in the vaccine have been killed and are not capable of causing infection.

The belief can be attributed to a variety of factors: a flu-like reaction to the virus (which isn’t actually influenza), catching an unrelated strain of flu, or not responding to the vaccine itself. But the vaccination itself can’t give you flu, so that’s not a reason to avoid a vaccination, especially if you fall into a potentially vulnerable category.

Monday’s medical myth: the flu vaccine will give you influenza [The Conversation]


  • Well done on posting this Angus. Great to see you dispel the myth, both to yourself and to everyone else. There is so much garbage spouted when it comes to vaccines, one of the great medical achievements of our time.

  • The Flu vaccine won’t give you the flu, but it may cause flu-like symptoms. Reminds me of Beaker and Professor Honeydew’s cure for poison Ivy – The one side effect was that it covered your body in a red, itchy rash.

  • call it bad luck, but the first time I ever got the flu bad enough to stay at home, was the time I got Flu Vac, 2 years in a row… last year, no vac, no flu. this year no vac… but so far I’ve had a bad cold for about 3-4 days that has been going around work and footy. No Vac for me thanks… Oh and I heard it only protects from 3 strains of the Flu… which made me wonder how many strains are there? oh… unlimited, it evolves every year and mutates… so really whats the point? The point is to make the owners & distributors lots of money!!!

    • The flu isn’t actually dangerous for a lot of people, but some people are at risk and can die from it. Apart from doing the best they can to protect themselves herd immunity helps reduce their chances of catching the flu. Each year vaccines are developed based on the strains that are out there and work to prepare your immune system to identify the flu virus and quickly destroy it. No medicine can ever be 100% effective and perhaps they didn’t work for you but there is solid science behind vaccines.

      • Solid science? More like big pharma! Fact is, while the flu vaccine might not give you the flu, for a healthy adult it does nothing to reduce your chance of being hospitalised or missing work from the flu. If you are not a child, or over the age of 65, there is no point in you getting a flu vaccination (and no, I’m not an anti-vaccination nut, I fully support and encourage everyone to get all vaccines that are proven to be effective and to do otherwise would be irresponsible).

        The Chocrane Collaboration (a World Health Organisation) partner NGO recently did a meta-analysis of flu vaccine trials and found: Authors of this review assessed all trials that compared vaccinated people with unvaccinated people. The combined results of these trials showed that under ideal conditions (vaccine completely matching circulating viral configuration) 33 healthy adults need to be vaccinated to avoid one set of influenza symptoms. In average conditions (partially matching vaccine) 100 people need to be vaccinated to avoid one set of influenza symptoms. Vaccine use did not affect the number of people hospitalised or working days lost but caused one case of Guillian-Barré syndrome (a major neurological condition leading to paralysis) for every one million vaccinations. Fifteen of the 36 trials were funded by vaccine companies and four had no funding declaration. Our results may be an optimistic estimate because company-sponsored influenza vaccines trials tend to produce results favorable to their products and some of the evidence comes from trials carried out in ideal viral circulation and matching conditions and because the harms evidence base is limited. (

        • The influenza vaccine is funded under the PBS for high risk groups. Ie: child care workers, health workers, the elderly, immunocompromised, some chronic lung disease. In these patients it is really important to stop them getting infected. In normal healthy adults you don’t strictly speaking need the vaccine. However it is prudent to stop yourself getting sick or passing it on to others (it can actually kill some of the previously aforementioned groups). Also that is not a particularly high NNT. Consider cancer drugs for instance. Its up to you whether you want it or not. I got mine last week

        • If the vaccine matches the circulating influenza strains….then they report 80% efficacy. That’s nothing to be sneezed at (sorry). If the vaccine formulation (the 3 viruses included are based on surveys of what mains flu viruses are circulating in the northern hemisphere and extrapolating to what we likely to see most of in Aus) was not the same as what the person is infected with (yes there are many other flu viruses from other years but they are GENERALLY not at epidemic levels because many have seen them and have some immunity to them…its a bit of crapshoot but better than fevers, myalgia, vomiting and a possible secondary bacterial pneumonia etc that you can get with a full-on flu). The conclusion from the Cochrane review, which you’ve misrepresented horribly, is that if the vaccine matches you get protection the majority of the time.

    • Its not unlimited. But there are many.

      Profit is not the point at all and that is a very cynical view yo have of life . The point is to help reduce disease and save some lives. A side-effect is that when you scale up to the level you need to to ensure safe delivery, you involve big business in a western society ‘s. Therefore there is ALSO profit to be made. These drug formulations never leave the oversight of real scientists and clinical researchers. Stow the conspiracy theory fairy tales on this one guys.

  • Also, flu is not the only virus that can give you flu-like symptoms. There are over 200 respiratory viruses and most, when first seen by the body, can produce nasty outcomes at some time or another. The common cold viruses, human rhinoviruses, are a great example. There were lots of rhinovirus cases during the recent influenza pandemic… could not be distinguished clinically from “influenza-like illness”.

  • Obviously the flu vaccine may contain viral cells which may not have been inactivated. So it can cause flu. Nothing is ever 100% guaranteed.

    • Hmm, not true, even if it somehow survived the manufacturing process – which is improbable, if not impossible, the virus would die in the syringe between manufacturing and delivery.

    • Firstly, a virus isn’t a cell, nor does it have any cell-like structure… secondly sure nothing is 100% guaranteed but what you’re saying can be 100% guaranteed to sound stupid.

  • Flu-like symptoms are, of course nothing even approximating full-blown influenza. Most people I have worked around are hypochondriacs at heart and any minor chest cold of feeling of malaise quickly becomes ‘the flu’

  • @john jaccobs
    Viruses are not cells. As such they cannot contain viral cells. Please refrain from making comments on an issue you know nothing about. Viruses are very simple proteins. This vaccine has proteins that have been 100% inactivated. Yes it only covers a few strains, but it is these fee strains that are the statistically most likely to cause illness that year
    Some people do feel feverish but that is just your body mounting the immune response to make antibodies to protect you. You do not actually get sick ie runny nose, coughing and sneezing

    • If you’re going to correct someone on a biological technicality, you should at least do it properly.

      Viruses are subcellular genetic elements. They must contain genetic data in the form of nucleic acids, and can then have ‘shells’ formed from protein, lipid envelopes, and even enzymes, all packaged up together.

      While they’re significantly less complex than a cell, they are hardly “very simple proteins.” That would be a prion. And, even then, I would hesitate to call a prion simple.

      • You know pitching something at a person’s level is a wonderful thing. I thought I’d start at level 1 considering john Jacobs was completely wrong. Thank you for semi correcting me. I liked the part where you added nothing to the discussion. Would you like to talk about surface antigens or fusion proteins too? Don’t be a wank for no reason. Just because I don’t write a thesis, doesn’t mean I don’t know it. Its all about pitching at the correct level…

  • Here’s a tip for all those who think they’ve gotten the flu after getting a vaccination. Not only did you not have the flu then, but you have probably never had it in your life. When you really have influenza, as opposed to a cold or other virus with flu like symptoms, you’ll know it. Compared to a cold, it’ll be like being hit by a train while you have malaria.

    • Absolutely! I think that I’ve had the ‘flu before. Once. Thirty(!) years ago. Not nice. At all.

      I had my ‘flu jab over a week ago now – and yes I had a reaction: a ‘poached egg’ on my upper arm for two days. Far rather that discomfort than avoid the needle.

  • To all of these people commenting and professing their knowledge of influenza and vaccines, how many of you have actually studied biological science or medicine? Think of the consequences or sprouting incorrect information and stick to what you know!

  • Mr James. It is correct that viruses aren’t cells but they are also more than simple proteins. They all have some form of nucleic acid (DNA or RNA) and some also have a lipid component

  • There are so many misconceptions and comments clearly without having a solid understanding of the subject.
    First of all, yes, viruses are NOT cells. They work by changing the transcription of proteins of your existing cells by altering the DNA. This is done by inserting the viral DNA or RNA into the nucleus of the cell. The cell is then effectively taken over by the virus, just like how your computer can be taken over by a virus, and then that cell can replicate and spread the illness. It is also important to understand that viruses are distinct from bacteria.

    Now @LG and a few others. Scientists will simply call potential side effects as “flu-like symptoms” as these symptoms are mainly just the body’s general non-specific immune response to foreign matter or pathogens. These flu-like symptoms are usually due to the release of chemical mediators such as histamine, prostagladins and interleukins, which all contribute to inflammation, vasodilation in affected area and recruitment of lymphocytes to cause further effects.
    @woodsdog. What do you define as “the flu”? So many people throw around disorders, illnesses and conditions without really knowing what it is. Please, learn what you’re talking about before talking about it! Then you bring in the common cold which is totally unrelated to influenza.

    • Sorry to be a pedant Ronald but respiratory viruses don’t alter the DNA. They take over the cell to make it do its bidding. Think Loki and his glowy staff. Also, one doesn’t change transcription of protein, one changes RNA transcription… translation makes protein (which is affected by transcription and its controllers…but not quite as directly as your note implies). Flu like symptoms are not used by scientist solely for describing the results of vaccine trials. They are (often) well defined symptoms that included fever plus a range of other signs or symptoms. The common cold is in fact very closely related to influenza in that presentation can be clinically indistinguishable. Just a note here – ALL respiratory viruses (there are >200) can manifest with “severe” signs and symptoms…or mild to unnoticeable (asymptomatic) signs ans symptoms. Even flu viruses.

  • As a budding vaccinologist/epidemiologist I thought this information was already well known. Perhaps I need to add public policy to my repertoire get this basic info out to the public.

    • Countering FUD (Fear, uncertainty and doubt) should be a core issue for all of us who work anywhere in the public health sphere. FUD and public policy: a potent combination!

  • Read carefully my friend. Emphasis is on THAT CAN. In Australia neither the prophylaxis nor the treatment is via any injection. They are tablets so this article is completely devoid. You must be careful what you read, or better yet see your doctor. That being said, given the correct information and in particular in the case of the flu shot, it is entirely up to you as you have said.

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