Very common, affecting more than 1 in 10 people at each dose:
- pain, redness and swelling at the injection site
- temperature of 38°C or higher
- feeling irritable or restless
- tiredness or feeling sleepy
- loss of appetite
- unusual crying
Common, affecting up to 1 in 10 people at each dose:
- feeling sick or being sick (nausea or vomiting)
- temperature of 39.5°C or higher
- hard lump at the injection site
- itching or skin inflammation in the area where the vaccine was injected
- generally feeling unwell or weak
- aching or swollen joints
Many of these symptoms can be relieved by giving paracetamol (Calpol) if your child is over 2 months, or ibuprofen if your child is over 3 months and weighs more than 5kg. See the NHS Website for more advice on giving painkillers to babies and children).
Very rare (affecting fewer than 1 in 10,000 people at each dose):
- high temperatures, sometimes leading to fits (also called convulsions or febrile seizures)
- unusual high-pitched screaming and hypotonic-hyporesponsive episodes (HHE), during which the child may become blue, pale and/or limp
You should consult your doctor if your child experiences fits or HHE episodes after vaccination. This is mainly to check that it is the vaccine causing the symptoms, and not some unrelated disease. Symptoms such as fits can be very worrying for parents, but there is no evidence of long-term effects. Children can normally safely receive vaccines in the future. For more information on febrile seizures generally, see the NHS Website.
As with any vaccine, medicine or food, there is a very small chance of a severe allergic reaction (anaphylaxis). Anaphylaxis is different from less severe allergic reactions because it causes life-threatening breathing and/or circulation problems. It is always extremely serious but can be treated with adrenaline. Healthcare workers who give vaccines know how to do this.
In the UK between 1997 and 2003 there were a total of 130 reports of anaphylaxis following ALL immunisations, although no deaths as a result of the reaction were reported. Around 117 million doses of vaccines were given in the UK during this period. This means that the overall rate of anaphylaxis is around 1 in 900,000.
If you are concerned about any reactions that occur after vaccination, consult your doctor. In the UK you can report suspected vaccine side effects to the Medicines and Healthcare products Regulatory Agency (MHRA) through the Yellow Card Scheme.
You can also contact the MHRA to ask for data on Yellow Card reports for individual vaccines. See more information on the Yellow Card scheme and monitoring of vaccine safety.