At around 13 months, your baby will be offered the MMR, the immunisation that protects against measles, mumps and rubella. Some parents have worries about this jab, so we round up the facts.

What does the MMR do?

It protects against three illnesses:

• Measles, a serious illness with a rash and fevers
• Mumps an illness which causes swelling around the jaws
• Rubella also known as German measles, this illness brings a rash and sore throat. If a woman who is not immune to the disease catches it in the first 3 months of pregnancy, there is a risk that her baby will be born with birth defects.

When is it given?

The MMR is given around 13 months. Tell the practice nurse on the day if:

• Your baby has a temperature/fever
• Has had a bad reaction to a previous immunisation
• Has any problems with bleeding
• Has ever had a fit or convulsion
• If any member of your family is taking medicines which affect the immune system, such as for cancer or following an organ transplant.
• If any member of your family has an illness such as HIV or Aids that affects the immune system.

Are there any side effects?

Soon after the immunisation, your baby may:

• Develop a fever
• Go off his food.
• Develop a rash on his body.

Your practice nurse might suggest giving paracetamol liquid or liquid ibuprofen to reduce your baby’s temperature and to soothe any pain. A medicine syringe (available from your pharmacist) is helpful in giving medicines to a baby. Do not give your baby aspirin! 

A very small percentage of children have had a fit after immunisation, but this is very rare.
To put this in perspective, a child who gets measles is 10 times more likely to have a fit as a result of the illness.

If your baby develops a very high temperature (over 39.4ºC/ 103ºF) or has a fit, consult your doctor at once. If the surgery is closed, go to your nearest A&E.

There is also a small risk of encephalitis (inflammation of the brain) but this is very rare. The risk of your baby developing encephalitis after the MMR immunisation is no higher than the risk of your baby developing encephalitis without the vaccine.

But if your baby gets measles infection, then it is very likely that he will have some degree of inflammation of the brain and very occasionally this can result in permanent damage.
Follow your instincts. If you think your baby is having a severe reaction to the immunisation, seek medical advice.

Fears about MMR

Parents do worry about the risk of complications from the MMR. There has been widespread media coverage of a possible link between the combined MMR immunisation and autism.
This concern was raised in a publication in 1998, but since then there has been extensive research from all over the world which has shown no link between autism and MMR.

Countries that changed the combined injection to separate single immunisations have not found any decrease in the rate of autism. The combined immunisation is better at protecting your baby than using 3 single injections and most health professionals are convinced of the safety of MMR. They highlight the risks of the diseases that the jab is designed to protect your baby against and the complications:

• Measles can lead to chest infections, fits and brain damage; before the vaccine was introduced, about 90 children in the UK died each year from measles.
• Mumps can lead to viral meningitis, deafness and swelling of the testicles and ovaries.
• Rubella seriously harms an unborn baby if a woman catches it for the first time during pregnancy.

Making your mind up

The chance of your baby having a complication from the MMR immunisation is tiny, but the risks from the diseases themselves are life-threatening. Remember, the vast majority of babies in Europe and the USA are given the MMR vaccination.

Egg allergy and vaccines

Some vaccines are produced using eggs but they remain safe even if your baby has had a reaction to eggs. However if you are concerned, or your baby has had a severe reaction to eggs, then discuss this with your doctor before your baby is immunised.