This information tells you about the common side effects of immunisations that might occur in babies and young children up to 5 years of age.
This information is to be used as a guide only. You should always seek advice from your GP or Health Visitor if you're worried.
After immunisations given to children under 5 years of age
The most common side effects are at the site where the injection was given, these include:
- 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. If you're still not happy with your baby’s reaction to any immunisation, speak to your practice nurse or GP.
How to treat a fever in children
Comforting your baby
It's 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 cool drinks (if you're breastfeeding, your child may feed more often)
- 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 the MMR vaccination
MMR is made up of 3 different vaccines (measles, mumps and rubella) which can cause reactions at different times after the injection.
Side effects after 6 to 10 days
After 6 to 10 days the measles vaccine starts to work and may cause a:
- measles-like rash
- loss of appetite
Side effects at 2 to 3 weeks
At around 2 to 3 weeks after the injection the mumps vaccine may cause mumps-like symptoms (fever and swollen glands) in some children.
Side effects at 12 to 14 days
Most commonly around 12 to 14 days after the injection, the rubella vaccine may cause a brief rash and possibly a slightly raised temperature. On rare occasions, a rash may also occur up to 6 weeks later.
Further information about NHS Vaccinations
More information on the side effects of vaccines and immunisations can be found in the leaflets: