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COVID-19 vaccines side effects and safety

Millions of adults and children around the world have had a COVID-19 vaccine and it gives you the best protection against COVID-19.

Like all medicines, the COVID-19 vaccines can cause side effects, but not everyone gets them.

The safety of the vaccines has been extensively reviewed in both adults and children by the independent Medicines and Healthcare products Regulatory Agency (MHRA).

The MHRA are continuously monitoring the safety of the COVID-19 vaccines and reports of serious side effects are very rare.

Find out more about the MHRA on GOV.UK

Common side effects of COVID-19 vaccination

Most side effects of the COVID-19 vaccination are mild and should not last longer than a week, such as:

  • a sore arm from the injection
  • feeling tired
  • a headache
  • feeling achy
  • mild flu-like symptoms
  • feeling or being sick
  • diarrhoea

You or your child should rest. You can also take pain relief such as paracetamol to help you feel better.

You cannot catch COVID-19 from the vaccine.

Read about what to expect after your COVID-19 vaccination on GOV.UK

Urgent advice: Contact 111 if:

You or your child have had a COVID-19 vaccine and:

  • have symptoms that are getting worse
  • you're worried about your or your child's symptoms

You can call 111 or get help from 111 online.

Very rare side effects of COVID-19 vaccination

Allergic reactions

Most people with allergies (including food or penicillin allergies) can be vaccinated against COVID-19.

If you've ever had a serious allergic reaction (including anaphylaxis), tell healthcare staff before you're vaccinated. They may ask what you're allergic to.

If you've had a mild allergic reaction before, such as a rash, wheezing or hives, you are likely to get a common COVID-19 vaccine. Staff giving the vaccine are trained to deal with allergic reactions and treat them immediately.

If you are at risk of a serious allergic reaction, they may refer you to a specialist clinic for your vaccination, or to have an alternative COVID-19 vaccine.

Heart inflammation (myocarditis)

There have been rare cases of inflammation of the heart (myocarditis) reported after COVID-19 vaccination. Most people who had this recovered following rest and simple treatments.

Find out more about myocarditis and COVID-19 vaccines on the British Heart Foundation website

Immediate action required: Call 999 or go to A&E if:

You or your child have any of these symptoms within a few days of being vaccinated:

  • chest pain or feeling of tightness in the chest
  • shortness of breath
  • a fast-beating, fluttering or pounding heart (palpitations)

More information

Page last reviewed: 21 March 2023
Next review due: 21 March 2026