The 4-in-1 pre-school booster is very safe but, as with all medicines, some babies do get side effects.
Side effects are generally mild and short lived and most likely to happen within 48 hours of the injection. Most children won't have any problems at all.
Very common reactions to the pre-school booster
More than 1 child in 10 having the pre-school booster vaccine get:
- loss of appetite
- increased crying
- mild fever
- discomfort, redness and swelling at the injection site
Common reactions to the pre-school booster
Between 1 child in 10 and 1 child in 100 who has the pre-school vaccine gets:
Uncommon reactions to the pre-school booster
Between 1 child in 100 and 1 child in 1,000 who has the vaccine gets:
- swollen glands
Rare or very rare reactions to the pre-school booster
Less than 1 child in 1,000 who has the vaccine has a fit (convulsion).
Severe allergic reactions
Very occasionally, 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 one in a million vaccinations.
If it happens, it will be within minutes of the vaccination, and the doctor or nurse giving the vaccine will know how to deal with it. Children recover completely with treatment.
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 two to three days and doesn't need any treatment.
If your child gets a fever (a temperature over 37.5C), 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 four to six 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 NHS 111.
To find out more, read Vaccine safety and side effects.
This NHS leaflet (PDF, 64.4kb) tells you the common vaccination reactions in young children up to five 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 Committee on Safety of Medicines.
Most reactions reported through the Yellow Card Scheme have been minor reactions, such as rashes, fever, vomiting, and redness and swelling where the injection was given.
Find out how to report a vaccine side effect.
Read more about the 4-in-1 pre-school booster vaccine.
Article provided by NHS Choices