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Treatment prevention

Flu vaccines

Having a flu jab each autumn is the most well-known way to prevent flu.

How do flu vaccines work?

Flu vaccines are made from inactivated (killed) flu viruses. Because the viruses have been killed, they cannot cause infection. However, they will make your body produce antibodies which can help protect you if you come into contact with the same flu viruses again that season.

The flu jab needs to be renewed each year. First, your protection against flu produced by the previous year’s vaccine naturally gets lower over time and so may not be sufficient to protect you against illness 1 year later. But most importantly, scientists have to make different flu vaccines every year because the strain of flu virus changes from year to year. [1] About 9–10 months before the flu season begins they prepare a new vaccine based on the virus strains expected to circulate that year in the southern or northern hemisphere. This is why people need to have a new flu jab each year to make sure they are protected against the latest flu virus strains.

Sometimes an unpredicted new virus strain may appear after the vaccine has been made and distributed to doctors’ surgeries and clinics. Because of this, even if you do get a flu jab, you may still be at risk of getting flu.

Who should be vaccinated?

Catching flu can be a nasty experience for all of us. However, for some people, flu can cause serious complications like bronchitis and pneumonia that may require hospital treatment.

Recommendations for who should receive the annual flu jab differ from country to country. However, most countries recommend a yearly flu jab for the following people:

  • people aged 65 years or older
  • people at high risk of developing serious flu complications – such as individuals with serious heart problems, asthma or chronic obstructive pulmonary disease (COPD), long-term liver or kidney disease, diabetes, or weakened immune systems
  • people who live with, or care for, those at high risk for serious flu complications
  • healthcare professionals.

If you are not sure whether or not you need a flu jab, check with your doctor or pharmacist.

Flu jab side-effects

Like most vaccines, flu jabs can have some side-effects. The most common side-effect is soreness at the site of the vaccination. Other possible side-effects include fever, tiredness and sore muscles. Side-effects typically begin 6–12 hours after vaccination and may last for up to 2 days.

Flu vaccines may also contain egg protein – which can cause an allergic reaction. This is because the viruses used in the vaccine are grown in chicken eggs, before being killed with a chemical so that they can no longer cause infection. [1, 2] It is important to talk to your doctor before getting vaccinated if you or a family member is allergic to eggs or has ever had a serious allergic reaction to the flu vaccine.

  1. Perrie Y. Influenza: treatment and prevention. Pharm J 2006; 277: 399–402.
  2. Stephenson I, Nicholson KG. Influenza: vaccination and treatment. Eur Respir J 2001; 17: 1282–93.
  • "I would describe flu as something that makes you feel very, very ill. You get a headache, aching bones, and are generally fed up"
  • "When I get flu symptoms I feel like a train has run over me"
  • "I felt very sick and, during the first week, I had high temperature. Flu was very different to a cold. I went back to work after two and a half weeks. Then I suffered a setback for another week"
  • "I run a guesthouse; flu would be a real pest for me. I couldn’t cook, I shouldn’t cook, and I wouldn’t cook, so I would need to get a lot of extra help in. It would cost me a lot more money. So flu’s a real problem, a right downturn"
  • "I work on my own and when I can’t work, I have to try not to infect my little children, so they avoid getting the flu as well"
  • "I feel a little numb, like I’m in another dimension. Because in general I have sore throat, headache, I feel all clogged-up. Usually a sensation like I’m floating in the air"
  • "Shivers, sweats, makes you ache. Last time I had flu I was off for two weeks"
  • "I think that I would probably be concerned that I would pass flu onto my children, who might not be able to deal with it as well as I would"
  • "Flu makes you feel like you’ve been hit over the head with a baseball bat. You don’t feel like you can get yourself out of bed as all your energy is drawn from you"
  • "I was incapable of working. It just wasn’t possible at all… and my flu dragged on for more than a week"
  • "I have no strength. It annoys me because I can do nothing, it seems like I’m wasting my time"
  • "Flu’s like being hit by a truck because you feel completely gone. There is no energy left in your body. You are suffering from high temperature. You’re sweating a lot and you feel really unwell"
  • "First of all infinite tiredness, then I feel like sleeping and don’t want to eat"
  • "I felt really miserable because my muscles and my bones were aching. Well, I can hardly describe it, I just felt really awful, absolutely miserable"
  • "It’s like there’s something huge treading on your head, like a deafening noise that destroys the eardrums"
  • "The fever was constantly rising – I immediately measured my temperature as soon as I got home. It was 41°C and it kept rising and I was wondering what’s going on. I was really scared! Everything was hurting and it all happened so fast. Flu came out of the blue"
  • "I always feel like my limbs have iron weights tied to them and I’m going to fall over any minute, a really stuffy runny nose and feel antisocial"
  • "I was totally dependent on others! I was incapable of doing anything at all"
  • "The real flu knocks you for six – you just don’t want to move or do anything. It’s not very nice"
  • "Not being able to go to work. Not being able to do the things I have to do at home and the commitments that I have day by day"