What to expect after Immunisation - Babies and children up to 5 years

This information tells you about the common side effects of immunisations that might occur in babies and young children up to five years of age.

Only use this information as a guide. You should always seek advice from your GP or health visitor if you are worried about your baby.

After immunisations given to children under five years of age

The most common side effects are at the site where the injection was given, these include:

  • swelling
  • redness
  • a small hard lump.

These symptoms usually pass within a couple of days and you don’t need to do anything about them. Sometimes your child may develop a fever-see the section below on ‘how to treat a fever’.
It is normal for your baby to be upset for up to 48 hours after having the injection. To help comfort your baby, you can:

  • give them a cuddle
  • offer them extra drinks
  • take them for a walk in the fresh air.

If the injection site is flushed, put a clean cold cloth to the area for about 5 to 10 minutes – this may help to soothe your baby.
After reading this guide, if you are still not happy with your baby’s reaction to any immunisation, speak to your practice nurse or GP.

After immunisation with MMR

MMR is made up of three different vaccines (measles, mumps and rubella) which can cause reactions at different times after the injection.

Side effects of MMR may include:

  • After 6-10 days the measles vaccine starts to work and may cause a fever, a measles-like rash and a loss of appetite.
  • Around 2-3 weeks after the injection the mumps vaccine may cause mumps-like symptoms (fever and swollen glands) in some children.
  • Most commonly around 12-14 days after the injection the rubella vaccine may cause a brief rash and possibility a slightly raised temperature, and on rare occasions a rash may also occur up to 6 weeks later.

How to treat a fever

A fever is a body temperature over 37.5°C. Fevers are quite common in young children, but are usually mild. If your child’s face feels hot to the touch and they look red or flushed, he or she may have a fever. You can check their temperature with a thermometer.

Keep your child cool by:

  • making sure they don’t have too many layers of clothes or blankets on (remove clothes)
  • turning down the house heating
  • giving them plenty of cool drinks (if you are breastfeeding, your child may feed more frequently)

You don't need to put them in a bath, sponge them down or put a fan on them. There is no evidence that this will lower your child's fever.

As fevers are usually mild, you only need to give a dose of infant paracetamol if your child appears uncomfortable or unwell. Read the instructions on the bottle very carefully. Please read separate advice, about using paracetamol after the MenB vaccine at 2 and 4 months of age, on our What to expect after immunisation: babies and young children sheet. 

Remember, never give medicines that contain aspirin to children under 16.

If you are worried about your child, trust your instincts. Speak to your doctor or call NHS 24 on 111 (freephone). Call the doctor immediately if, at any time, your child has a temperature of 39-40oC or above, or has a fit.

If the surgery is closed and you can’t contact your doctor, go to the nearest hospital with an emergency department.

Checking on vaccine safety

Before vaccines are introduced, they have to be licensed by the Medical and Healthcare products Regulatory Agency (MHRA) which assesses their safety and efficacy. Once they have been introduced, their safety is constantly monitored so that any new side effects are quickly noticed and investigated. For more information on the safety of vaccines visit: www.mhra.gov.uk

Yellow Card Scheme

Parents and carers can also report suspected side effects of vaccines and medicines through the Yellow Card Scheme. This can be done by visiting www.yellowcard.gov.uk or by calling the Yellow Card hotline on 0808 100 3352 (available Monday to Friday – 10 am to 2 pm).

More information

More information on the side effects of vaccines and immunisations can be found in the leaflets A guide to childhood immunisations up to 5 years of age and What to expect after immunisation: babies and young children which can be found at [bold www.immunisationscotland.org.uk or at your local GP surgery.


Last reviewed on 28 August 2015

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