Will the flu vaccine definitely stop you from getting the flu?

The flu vaccine doesn’t provide complete protection.

woman with influenza

Flu vaccine won't definitely stop you from getting the flu, but it's more important than you think

While the flu vaccine cuts your chance of coming down with influenza, that’s not the whole story.

Allen Cheng, Monash University and Kristine Macartney, University of Sydney

As we head towards a southern hemisphere winter, many people are wondering if it’s worth getting the flu vaccine. The Conversation

Generally speaking, if you are vaccinated, you’re less likely to get the flu. But that’s not the whole story.

For most healthy people, it’s about considering the cost and a few seconds of pain against the possibility that you’ll need to take time off work and endure a few days of misery due to infection.

For people who come into contact with vulnerable people – like the elderly, young or sick – getting vaccinated reduces the risk that you can pass it on.

For vulnerable people, the flu can be the difference between being at home with a chronic disease, and being in hospital with complications such as bacterial pneumonia.

When you should get vaccinated is a bit like playing the lottery. If you are vaccinated too early, there’s the risk it doesn’t work when you most need it; too late and you may get the flu while unprotected, or forget to have it before flu season hits.

Here’s what you need to know when deciding whether to get vaccinated, and when.

Preventing influenza

People who get vaccinated are at lower risk of getting influenza than those who are not. They are less likely to be laid up in bed with sweats, shivers and muscle aches, and take time off work or their usual activities, or be hospitalised with complications.

The Australian government recommends everyone from six months old be vaccinated, with those in the following higher-risk categories eligible for a free shot in 2017:

  • people aged 65 years and over
  • Aboriginal and Torres Strait people aged six months to less than five years
  • Aboriginal and Torres Strait Islander people who are aged 15 years and over
  • pregnant women
  • people aged six months and over with medical conditions, like severe asthma, lung or heart disease, low immunity or diabetes that can lead to complications from influenza.

The mild symptoms that some people get after vaccination are usually related to the vaccine generating an immune response. This is how vaccines work - by “training” the immune system to recognise parts of the influenza virus, it can respond more effectively when it encounters the real thing. There is no “live virus” in the flu shot. Your body responds to parts of the flu virus in the vaccine; you cannot “catch the flu” from it.

All brands of flu vaccine available in Australia are safe; researchers are continuing to monitor for any side-effects week-by-week using SMS feedback from people who have been recently vaccinated.

Like all medications, the flu vaccine carries with it a small risk of side effects, like temporary soreness at the injection site.

The flu vaccine doesn’t provide complete protection

Most clinical trials that have looked at how effective the flu vaccine is were performed in healthy adults and children. However, the people for whom we strongly recommend flu vaccine are those who are older and with chronic illnesses. Unfortunately the vaccine doesn’t elicit as strong an immune response in these groups. They are targeted for vaccination because of the high risk of complications.

In Australian studies, we generally estimate the risk of influenza is reduced by about 40-50% in people who receive the vaccine.

While this might seem low, reducing the risk of infection by half is worth the effort.

There are a number of different strains of influenza, which are categorised into types, subtypes and strains. For example, one of the four strains in the 2017 vaccine is called A/H3N2/Hong Kong/4801/2014, which refers to an influenza A type, a H3N2 subtype (flu viruses are defined and named by proteins on their surface, haemagglutinin - H, and neuraminidase - N), and a strain first isolated in Hong Kong in 2014.

In a typical year, there are usually three subtypes (in varying proportions) of the influenza circulating that cause disease. Except in pandemic years, the circulating strains are usually variants of the previous season’s strains, and this allows the World Health Organisation to make recommendations on which strains should go into the next season’s vaccine.

Occasionally, the vaccine strains aren’t well matched to circulating strains. This risk of mismatch has been reduced by the quadrivalent vaccine that contains four strains.

Protection from the flu doesn’t last that long

In most of Australia, the peak flu season usually runs from August to September.

But the flu vaccine produces a relatively short-lived immune response, about 6-12 months after vaccination. This is because the flu vaccine produces a weaker immune response than being infected.

How long it provides protection probably depends on the patient (some studies show elderly patients have a shorter immune response) and the virus (some influenza subtypes elicit a stronger immune response than others).

So there is some concern that if people are vaccinated too early in the year, their immune response might be starting to decline just when it is needed.

Studies that have looked at how important this is have shown conflicting results. While one study found the effectiveness of the vaccine against the A/H1N1 and A/H3N2 strains declined after three months, the other study found a decline only against A/H3N2 and B strains.

In the meantime, we generally recommend April to June is probably the optimal time for vaccination – early enough for your immune system to “learn” how to deal with the influenza virus for the peak flu season, but not so late you miss the peak flu season.

For doctors, there are other factors involved in deciding when to vaccinate a patient. If they don’t vaccinate a patient now, will they come back again before the influenza season hits? Are they are risk of getting influenza “out of season”?

Although most flu cases occur in winter, we are increasingly aware of cases that occur throughout the year. This is particularly important in tropical regions where influenza tends to circulate all year round.

Allen Cheng, Professor in Infectious Diseases Epidemiology, Monash University and Kristine Macartney, Associate Professor, Discipline of Paediatrics and Child Health, University of Sydney

This article was originally published on The Conversation. Read the original article.





    COMMENTS

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    Joy Anne
    14th Apr 2017
    9:14am
    Yes it is, I have had it for the last few years and have never once been sick in Winter with flu. I am extremely happy as I use to get Bronchitis, I also had the Bronchitis injection which is so good not to get sick in winter. You get 2 injections 5 years apart for this one.
    jackie
    14th Apr 2017
    2:52pm
    Joy I agree with you. I have been getting a jab for the past 4 years and haven't caught a thing.

    I had an early shot yesterday. The nurse told me they have been treating many people with the flu lately. All have arrived from overseas.

    So the flu has arrived earlier.
    Joy Anne
    14th Apr 2017
    9:14am
    Yes it is, I have had it for the last few years and have never once been sick in Winter with flu. I am extremely happy as I use to get Bronchitis, I also had the Bronchitis injection which is so good not to get sick in winter. You get 2 injections 5 years apart for this one.
    Blondie
    14th Apr 2017
    10:44am
    Works for me! No 'flu for several years. There is now a vaccination against shingles, my doctor offered me....can be quite serious and painful for the elderly!
    Blondie
    14th Apr 2017
    10:44am
    Works for me! No 'flu for several years. There is now a vaccination against shingles, my doctor offered me....can be quite serious and painful for the elderly!
    Blondie
    14th Apr 2017
    10:44am
    Works for me! No 'flu for several years. There is now a vaccination against shingles, my doctor offered me....can be quite serious and painful for the elderly!
    Charlie
    14th Apr 2017
    2:02pm
    You got no flu but maybe computer has got it and is slow on the uptake, sometimes this happens with mine but I never know till the message repeats
    Jen50
    14th Apr 2017
    10:44am
    I used to get flu injections at work every year but since I retired just over 3 years ago I never got around to having them until this year. I just happened to see a notice in a chemist window in my local shopping centre & went in to make an appointment. They were free at that moment so I had it done straight away and, being over 65 (a tiny bit over, lol), I only paid $10. I had some sort of virus last year but I don't think it was flu because it didn't seem severe enough. Prior to that the only other times I had flu were a couple of times in the mid 1970's when I worked on a large academic campus. I was so ill I was bedridden for several days and that's not something I want to go through at my age.
    jackie
    14th Apr 2017
    2:55pm
    Jen50 They cost everywhere $9 to $10....They are free for all health care card holders.
    rtrish
    14th Apr 2017
    10:55am
    Definitely worth it for me. I have chronic medical conditions so my GP advised the flu vaccine every year since. Also I have just found out I have mild COPD (chronic obstructive pulmonary disease) so it's even more essential I take care. In about 2007/08 my immune system was very low (turns out my sleep quality was poor; I had sleep apnoea and needed to go onto CPAP. Poor sleep can affect the immune system). That year I did get a dose of the flu. The GP said I would have been much sicker if I hadn't had the flu shot.
    ROB
    14th Apr 2017
    11:04am
    We simply keep our Glutathione levels raised. NO injections and have never had issues with flu for years. We travel constantly on planes and ships worldwide. Many of our friends do have the injections and they are the ones that still suffer with flu symptoms, often for weeks each year and especially if on cruises despite all the precautions. We do wonder ourselves how effective the injections are but that is just our experience. However it is important to understand exactly what is in the injections, even for Shingles - they are also a worry. We have specialists from London even contacting us about these issues and they are finding the Non Transdermal patches are the safest and most effective way of easing the pain and symptoms of Shingles and other issues. Australia is still lagging behind with technology, but we are learning :)
    Triss
    14th Apr 2017
    1:29pm
    I'm a great believer in vaccination but I had a flu jab many years ago and I came down with the worst case of flu I ever had. That could have been pure coincidence but no more jabs for me and I haven't had the flu, or a cold, since then. I'm vegetarian, I don't know whether that helps my immune system along.
    KSS
    14th Apr 2017
    5:45pm
    I do wish that people would stop with the fallacy that having the flu shot causes infection. It is impossible for this to happen given the virus in the vaccination is dead! You may well have got sick but it was not associated with the vaccination.
    Old Geezer
    14th Apr 2017
    7:34pm
    I was given a flu shot as a kid and it's the only time I have ever had the flu. In those days you had to have two shots to be effective but there was no way I was going to have the second one.

    Nearly every nursing home gets locked down every year due to the outbreak of flu. What I have trouble understanding is that all the residents have had a flu shot so why does this happen? Only explanation is that the flu shot is of little value.

    Have you also noticed that only unhealthy people gets the flu? So just stay healthy and that's the best protection one can have against any disease. For peace of mind have your flu shot but to me it's effectiveness is minimal if anything.
    musicveg
    14th Apr 2017
    7:57pm
    Yes OG, only unhealthy people get sick because their immune system is not working properly. My mum just told me of two of her friends that got the shakes after flu shots, makes you wonder what the ingredients are. Personally I keep healthy with lots of fresh leafy greens, antioxidant fruit like berries and olive leaf extract. I don't even get colds. Getting out in the fresh air to clean out your lungs everyday in winter is also beneficial. Too much heating and stuffy rooms breeds germs.
    Kate
    14th Apr 2017
    11:58am
    Perhaps we should be lobbying our government health departments to provide FREE flue jabs to everyone suitable to have the jab. Surely this could reduce winter hospital peaks by reducing the severity of symptoms which in turn saves on the cost of hospitalisation.
    Charlie
    14th Apr 2017
    1:54pm
    One of the reasons flu vax is done yearly is because the flu virus changes itself so frequently. I am over 65 with chronic illness so it is a definate yes for me every year.

    I would always get at least 2 colds a year of a couple weeks duration each, then one serious cough cold, like the flu, of six weeks duration about every 3 years.

    I have been out of the work environment for 10 years and don't go out at night anymore and I haven't had so much as a sniffle all that time.

    I also firmly believe in washing the under side of the hand which is the part that rests on coffee tables, counters and sometimes teller machines.
    musicveg
    14th Apr 2017
    7:58pm
    Might be good if everyone wore gloves when they go out in public and not sneeze or cough on people.
    johninmelb
    14th Apr 2017
    1:58pm
    I suffer badly from Bronchitis so I make sure I have my flu injection every year without fail. I know there is no guarantee, but it has kept me in better health than in the past. I have never had a bad reaction to Fluvax, but that is not say I won't one day. I am also one of the very few people who actually know that Fluvax won't give you the flu.

    However, one of the problems we have is that most people do not understand the difference between a cold, and the flu. Almost everyone thinks they are the same, and nothing will shift that thought from their stupid heads.

    The flu injection will assist in stopping you getting flu, BUT IT WON'T stop you getting a cold. And therein lies my problem, I catch a cold, and unless I get to the doctor quick enough before it goes to my chest, I can end up with acute Bronchitis very quickly. After donkey's years of research, we are still no closer to a cold cure.
    LiveItUp
    14th Apr 2017
    2:13pm
    Nope why protect yourself against last year's flu? Better to be healthy without all those poisons in your system. Never had the flu myself even when everyone else gets it.
    PAYEdmydues
    14th Apr 2017
    2:44pm
    Bonny, This is one rare occasion when I have no difficulty in disagreeing with you.
    I've had bouts of bronchial pneumonia in the past and since have been having yearly flu jab. Protection limited to a few serious viruses that you may or not come in contact with. You can increase your protection by disciplined personal hygiene such as not coming into close contact, washing frequently, not touching your face after possible contact etc. Works for me.
    halona
    14th Apr 2017
    7:34pm
    Totally agree with you Bonny. Never had one, never get a bad cold. Husband the same. Eat well and organic...oh, and we are both over 70...
    musicveg
    14th Apr 2017
    8:01pm
    I agree, prevention is the best cure, couple of doses of olive leaf extract boost your immune system as well as organic fresh veg and fruit.
    Young Simmo
    14th Apr 2017
    2:48pm
    Well I am a 100% supporter of the Flu Vac. I had only had an occasional Vac up till 1998, when I had one in Coolgardie and have not had a sniffle since. Now at 77 and with 19 clean years, there is no way I will miss out.
    Supernan
    14th Apr 2017
    5:26pm
    Havent had flu since started flu needles. No it doesnt protect from all flu. The vaccine is against the 4 worst strains that killed or hospitalised people in the past northern winter. You can still get other kinds of flu - generally the milder forms.
    Pardelope
    14th Apr 2017
    5:30pm
    Viruses for flu and colds belong to genetic "families". Their genetic makeup remains similar over the years but mutates over time. This results in many different versions which may infect a population. Having the vaccine protects you from the versions considered to be most dangerous or most likely to be encountered during the coming season.

    If you have a bad bout of flu or a bad cold after a vaccination, it may mean that you came in contact with a version which was not included - or you might have been even more ill without the vaccine. Personally, if I had a bad bout, I would be even more inclined to take the next seasonal vaccine.

    Children and young adults tend to get flu or colds more often for three main reasons. One is that they have not previously had contact with many forms of the virus. The second is that their lifestyle contributes - for example, they generally have many contacts with other people or places. The third is lack of basic awareness, ignorance, or past experience - which may lead to poor hygiene practices, mixing with people who are already sick, or underestimating the possible seriousness of these infections.

    Some adults should definitely improve their chances of survival by having vaccines e.g. if their immune system is weakened of if their lifestyle exposes them to increased risk of infection. These considerations should be discussed with their doctor.
    johninmelb
    14th Apr 2017
    5:48pm
    And children and young adults are no longer taught to use handkerchiefs and cover their mouth when coughing.

    It drives me mad. I am so glad I am retired. While I was working and having to travel on the train every day with these morons, I was constantly sick.

    One journey I had to endure a schoolgirl with a runny nose, constantly wiping it on her sleeve. Think about that for a moment, it will put you off your dinner tonight, it was so revolting.

    Not only that, they will not stay home when sick, out with their mates all night etc, spreading their germs everywhere. They try to get out of going to school, but won't give up a night out in the cold, wearing next to nothing.

    They don't know, and they don't care.
    Kez
    14th Apr 2017
    7:14pm
    Just curious - if the vaccines don't contain "live" viruses, then how do dead viruses protect us? I was always under the impression that we got a tiny bit of "live" viruses.
    musicveg
    14th Apr 2017
    8:11pm
    Yes it is a mystery, and the list of ingredients is a protected secret. Currently in USA a lot of people are discussing the ingredients of vaccines and why babies and children are having so many. Check out 'The truth about vaccines'

    https://go2.thetruthaboutvaccines.com/docuseries

    14th Apr 2017
    8:06pm
    https://go.thetruthaboutvaccines.com/?a_bid=62acb2d5&a_aid=TheDr&

    Incredibly disturbing animation reveals how vaccines are really made…
    https://justice4poland.com/2017/04/08/incredibly-disturbing-animation-reveals-how-vaccines-are-really-made/

    inf_contact_key=f3a71442e6623a5e5902e644130249906624f94f92d67a5be0ad03a520cef8d2

    https://www.ncbi.nlm.nih.gov/pubmed/24672722?inf_contact_key=2071bb0910f365ba1a1449505e912212f5e2fa3a64403fc41a545324f6fc0988

    14th Apr 2017
    8:10pm
    The Truth About Vaccines documentary series just launched hours ago...

    http://newstarget.com/2017-04-13-the-truth-about-vaccines-documentary-series-just-launched-hours-ago-view-the-cant-miss-episodes-here.html
    musicveg
    14th Apr 2017
    8:14pm
    I just posted the same link just as you did, I haven't watched yet due to limited data but have read a lot, the truth is coming out slowly, Big pharma has had their run of earning billions of dollars without informing people the ingredients used and how safe it really is (is not).
    musicveg
    14th Apr 2017
    8:17pm
    Lemons and limes are always ready to use just before the 'flu' season, so boost up your Vitamin C by squeezing a little on your green salad everyday. Most people don't consume enough Vitamin C and we don't store it.
    GoldenOldie
    14th Apr 2017
    8:24pm
    I have the flu jab every year with no side effects and nothing worse than a mild short-lived cold per year. Howevet after sharing a coach with folk coughing and sneezing I was diagnosed with Influenza A while on an Asian cruise. I have never felt so ill and was happy to endure my isolation from other passengers while taking very expensive anti-viral mdedication. How much worse it could have been without a flu jab I shudder to think!
    The pom
    14th Apr 2017
    8:44pm
    It must be 25 years ago I missed having a flu shot and got flu. I was a very fit person who had recently given up running marathons and racing bikes. I was a very sick person and needed 3 weeks to recover. I make sure I don't miss my injections
    Jolly
    14th Apr 2017
    9:47pm
    Ok 2 things about the flu vac...
    1. It is free for over 65's
    2. We do not need you antivaxers on here with your lies. There are some vulnerable people on this site, so they don't need your bulls@#$. I have been vaccinated since i was a baby and have not had any issues.
    musicveg
    14th Apr 2017
    9:56pm
    There are no anti-vaxers here just people concerned with what the ingredients are and asking questions to find out if they really work. Great to hear it works for some, but not everyone needs it.
    Young Simmo
    14th Apr 2017
    10:56pm
    Yes Jolly I agree and have had 18 years of Vacs and been flu free, but you will always get the knockers who are too dumb to make a reasonable statement so they knock everything. You watch I bet musicveg will say something nice about me.
    Janran
    15th Apr 2017
    12:57pm
    Pro-vaxers would have a much better argument (and take-up of a large variety of vaccinations) if the vaccinations didn't include a lot of very suss, toxic ingredients.

    I have a nephew who was given the triple antigen vax at 6 months of age and he's never been the same since. While his younger and older siblings thrived and flourished, he has struggled all his life. He is still a gorgeous young man and well loved by all, but unfortunately, he's still financially dependent on his ageing parents.

    His parents are convinced the vax caused mild autism, which should never have been administered to a baby with a fever (which he had at the time), but the doctors insisted "He's 6 months old so he must have the vax now." Heart-breakingly and ironically, the parents were accused of neglect when the baby wasn't thriving properly.
    musicveg
    15th Apr 2017
    1:04pm
    Janran, there are many cases similar to your nephews, my friend who is a nurse said the same about her son who is on the autism spectrum. Babies are just getting far too much too soon and their little bodies cannot cope. You only have to look at the amount of vaccines they are having now compared to 20, 30 and 40 years ago.
    Beeman
    15th Apr 2017
    12:06am
    I haven't suffered from flu but, then, I don't have the vaccine. Maybe when I get older and give up work I'll have to think about it but for now, as I'm only 88, I'll put it on hold.

    Several of my friends have used them but they then spend so much time off work that they are talking of "No more"

    Maybe it starts as a child when we were always put outside, even in the pram, in a cold country every day to develop an immune system.
    Blossom
    30th Apr 2017
    11:55pm
    They ae available at a younger age if you have certain disabilties and can be triggered by infections which cause a high temperature or trigger a neurological problem
    Blossom
    30th Apr 2017
    11:55pm
    They ae available at a younger age if you have certain disabilties and can be triggered by infections which cause a high temperature or trigger a neurological problem


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