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4-in-1 pre-school booster side effects

The 4-in-1 pre-school booster has been thoroughly tested and has a good safety record.

Although many children will not have any problems after vaccination, some children may have side effects.

These are usually mild and do not last long. They usually happen within 48 hours of the injection.

Very common side effects of the 4-in-1 pre-school booster

More than 1 child in 10 having the 4-in-1 pre-school booster vaccine may have:

  • discomfort, redness and swelling at the injection site
  • loss of appetite
  • irritability or restlessness
  • increased crying
  • high temperature (fever) of 38C or above

Common side effects of the 4-in-1 pre-school booster

Up to 1 in 10 children having the 4-in-1 pre-school booster may have:

Uncommon side effects of the 4-in-1 pre-school booster

Between 1 child in 100 and 1 child in 1,000 who has the vaccine may have:

Severe allergic reactions

Very rarely, a child has a severe allergic reaction, known as anaphylaxis, soon after the 4-in-1 pre-school booster.

This can happen with any vaccine and is extremely rare. It happens in fewer than 1 in a million vaccinations.

If it happens, it'll be soon after the vaccination and the doctor or nurse giving the vaccine will know how to deal with it.

Children treated promptly make a good recovery.

What to do if your child has a side effect

Some children have some swelling, redness or a small hard lump where the injection was given, and it may be sore to touch.

This usually only lasts 2 to 3 days and does not need any treatment.

If your child gets a temperature over 38C, you can treat them with paracetamol liquid.

Read the instructions on the bottle carefully and give your child the correct dose for their age.

If necessary, give them a second dose 4 to 6 hours later.

If your child's temperature is still high after they have had a second dose of paracetamol liquid, speak to your doctor or call 111.

Find out more about vaccine safety and side effects

This NHS leaflet (PDF, 64.4kb) tells you the common vaccination reactions in young children up to 5 years of age and how to treat them.

Monitoring the safety of vaccines

In the UK the safety of vaccines is routinely monitored through the Yellow Card Scheme by the Medicines and Healthcare products Regulatory Agency (MHRA) and the Commission on Human Medicines.

Most reactions reported through the Yellow Card Scheme have been minor reactions, such as rashes, fever, getting sick, and redness and swelling where the injection was given.

Find out how to report a vaccine side effect

Find out more about the 4-in-1 pre-school booster vaccine

Page last reviewed: 27 June 2019
Next review due: 27 June 2022