Why vaccination is safe and important

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Side effects of vaccination

Most of the side effects of vaccination are mild and do not last long.

The most common side effects of vaccination include:

  • the area where the needle goes in looking red, swollen and feeling a bit sore for 2 to 3 days
  • babies or young children feeling a bit unwell or developing a high temperature for 1 or 2 days

Some children might also cry and be upset immediately after the injection. This is normal and they should feel better after a cuddle.

Allergic reactions

It's rare for anyone to have a serious allergic reaction to a vaccination. If this does happen, it usually happens within minutes.

The person who vaccinates you or your child will be trained to deal with allergic reactions and treat them immediately. With prompt treatment, you or your child will make a good recovery.

Read vaccination tips for parents, including what to expect after vaccination.

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    • you're-not-sure-if-you-or-your-child-can-have-a-vaccine


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    Speak to your GP or practice nurse if:

    • you're worried about you or your child having a vaccine
    • you're not sure if you or your child can have a vaccine

    You could also ask a health visitor any questions you have about vaccines.

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    What's in a vaccine?

    Most people are not concerned about vaccine ingredients and know that they are safe.

    The main ingredient of any vaccine is a small amount of bacteria, virus or toxin that's been weakened or destroyed in a laboratory first.

    This means there's no risk of healthy people catching a disease from a vaccine. It's also why you might see vaccines being called "live" or "killed" vaccines.

  • Other vaccine ingredients

    Vaccines sometimes contain other ingredients that make the vaccine safe and more effective.

    There is no evidence that any of these ingredients cause harm when used in such small amounts.

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    A full list of any vaccine's ingredients is available on the electronic medicines compendium (emc) website.

  • specific-vaccine-ingredients-on-the-oxford-university-vaccine-knowledge-project-website.


    Read more about specific vaccine ingredients on the Oxford University Vaccine Knowledge Project website.

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