MMR is the combined vaccine that protects against the following diseases:

  • measles
  • mumps
  • rubella

The vaccine was introduced in Ireland 1988. Since then, the number of children who catch these diseases has fallen.

The first MMR vaccination is given to children at 12 months of age by their GP. A second dose is given to children aged 4-5 years in junior infants in primary school (except in Sligo, Leitrim and Donegal where it is given by a GP).

The vaccine contains weakened versions of live measles, mumps and rubella viruses (see box, left). Because the viruses are weakened, people who have recently had the vaccine cannot infect other people.

Measles, mumps and rubella have serious complications, which is why it is important that your child is vaccinated against them (see Why it should be taken, above).

How the MMR vaccine works

The vaccine triggers the immune system to produce antibodies against measles, mumps and rubella, as though your body had been infected with them. Antibodies are proteins that are produced by the body to neutralise or destroy disease-carrying organisms and toxins.

This also teaches your immune system how to produce the appropriate antibodies quickly.

If you then come into contact with one of the diseases, your immune system will recognise it and immediately produce the antibodies needed to fight it.

Measles, mumps and rubella are diseases that have serious complications:

  • Measles can cause a range of symptoms, which can include ear infections, pneumonia, bronchitis, encephalitis (inflammation of the brain), convulsions (fits) and brain damage. Measles can be fatal.
  • Mumps can cause viral encephalitis (inflammation of the brain). It also causes deafness, miscarriage, inflammation of the pancreas and pain and swelling in the testicles in men.
  • Rubella causes major birth defects in unborn babies and may cause miscarriage if the mother gets rubella in pregnancy. Babies may have some degree of deafness, blindness and damage to their heart or brain.

See Useful links for more information on these diseases.

There has been some controversy about the MMR vaccine in recent years, following a study published in The Lancet in 1998 by Dr Andrew Wakefield. His initial study appeared to show a link between the MMR vaccine and autism and bowel disease. However, his research was not carried out correctly and has since been discredited.

Extensive research into the MMR vaccine, involving thousands of children, was carried out in the UK, the USA, Sweden and Finland. This research showed that there is no link between MMR and autism. One study looked at every child born in Denmark from 1991 to 1998. During that time, 82% of children born in Denmark received the MMR vaccine. The researchers looked at the records of over half a million children and found the risk of autism was the same in immunised children as in children who had not been immunised. In 2010 Andrew Wakefield’s name was removed from the medical register after his research was discredited. Experts from around the world, including the World Health Organization, agree that there is no link between MMR and autism.



The first MMR vaccination is given to children at 12 months of age.

Children are given a second dose when they start school (usually between four and five years of age). 

Between 5 and 10% of children are not fully immune after the first dose. The booster gives increased protection, and less than 1% of children remain at risk after it (see box, left).

Women considering pregnancy

Women whose protection from rubella is low or uncertain are routinely offered a dose of Rubella vaccine. Rubella vaccine is only available as MMR vaccine.

Women who are considering becoming pregnant who have not had two doses of MMR vaccine should ask their GP about MMR vaccine.

Rubella in pregnancy can cause serious problems in the developing baby. Doctors advise women to avoid becoming pregnant for one month after vaccination with MMR. Pregnant women who were not screened before conceiving and who find out (through routine antenatal blood tests) that they are not immune will be offered a MMR vaccine after delivery of the baby.

Protecting people in a measles outbreak

In the event of a measles outbreak, MMR can protect people who have come into contact with the disease in the previous three days. This is because measles antibodies develop more quickly following vaccination than they do following natural infection.

Current advice states that there are no negative effects from vaccinating people who are already immune (for example, if there is any doubt whether they have already been vaccinated).

Why does my child need 2 doses of MMR vaccine?

A second dose of vaccine has been shown to significantly increase protection. 90% of children have a good response to the first dose, 99% of children have a good response to a second dose.

Parents or carers of children aged 12 months of age will be invited to make an appointment with their GP surgery for the MMR vaccination. Parents or carers of children who are 4 to 5 years of age will be invited to consent to vaccination of their child in junior infants in primary school. Those living in Sligo, Leitrim and Donegal will be asked to make an appointment with their GP for vaccination.

The vaccine is given as a single injection into the muscle of the thigh or upper arm. There may be some redness and swelling where the injection is given, but this should soon disappear.

There are no licensed single vaccines in Ireland for measles, mumps or rubella. The official licensing process is a form of quality testing to ensure that the products are safe and effective.

The HSE strongly recommends that children have the MMR vaccine to prevent putting them at risk of these serious illnesses.

After getting the vaccine, there may be discomfort, redness or swelling where the injection was given. Children may be irritable and have a fever. If this happens you can give them paracetamol or ibuprofen. You should also give them plenty to drink. Make sure they are not too warm and that their clothes are not rubbing against the injection area.

After 6 to 10 days 1 in 20 children may get “mini measles” with a rash and fever. About 1 child in 100 may get “mini-mumps” with swelling in the jaw area in the third week after vaccination. These are not contagious. Children usually recover from these side effects in a day or two.

Rare side effects

In rare cases, a child may get a small rash of bruise-like spots about two weeks after the injection. This side effect, linked to the rubella vaccine, is known as idiopathic thrombocytopenic purpura (ITP).

It has been estimated that ITP develops in less than one in every 22,000 doses of the MMR vaccine and that there is a greater risk of developing the condition from the diseases that the vaccine prevents.

ITP usually gets better on its own, but, as with any rash, seek advice from your doctor as soon as possible.

In very rare cases, children can have severe allergic reactions straight after an immunisation. This happens in about one in 100,000 immunisations for MMR. Medical staff who give immunisations are trained to deal with allergic reactions to vaccines.

People who have been recently immunised cannot infect others with the viruses contained in the MMR vaccine.

There are very few people who should not get the MMR vaccine. Your child should not get the vaccine if they have had a true allergic reaction (anaphylaxis) to a previous MMR vaccine or any part of the vaccine.

You should delay getting the vaccine if your child: 

  • is ill with a fever
  • has had another live vaccine, e.g. the BCG vaccine, within the previous four weeks 
  • is on high dose steroids
  • is having any treatment such as chemotherapy or radiotherapy
  • is on treatment with Protopic ointment for severe eczema
  • has any illness or disease that affects their immune system

 If you have any concerns, talk to your family doctor or public health nurse

Content provided by NHS Choices and adapted for Ireland by the Health A-Z.

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