NHS 111 Wales

MMR is a safe and effective combined vaccine that protects against three separate illnesses – measles, mumps and rubella (german measles) – in a single injection. The full course of MMR vaccination requires two doses.

Measles, mumps and rubella are common, highly infectious conditions that can have serious, potentially fatal, complications, including meningitis, swelling of the brain (encephalitis), and deafness.

They can also lead to complications in pregnancy that affect the unborn baby and can lead to miscarriage.

Since the MMR vaccine was introduced in 1988, it's rare for children in the UK to develop these serious conditions. However, outbreaks happen and cases of measles in particular have been rising in recent years, so it's important to make sure your children and yourself are up-to-date with MMR vaccination.

MMR vaccine for babies and pre-schoolers

MMR vaccine is given on the NHS as a single injection to babies as part of their routine vaccination schedule, usually within a month of their first birthday.

They will then have a second injection of the vaccine before starting school, usually between the ages of three and five.

The MMR vaccine can sometimes be given to babies from six months of age if they may have been exposed to the measles virus, or during a measles outbreak.

Babies under six months old are not routinely given the MMR vaccine. This is because the antibodies to measles, mumps and rubella passed from their mothers at the time of birth are retained and can work against the vaccine, meaning it’s not usually effective. However, this means the risk of any side effects is even lower among these younger babies, because the antibodies passed from the mother stop the viruses in the vaccine from growing. These maternal antibodies decline with age and are almost all gone by the time that MMR is normally given – around one year old.

In certain circumstances, for example during a measles outbreak, MMR vaccination is recommended for six- to nine-month-old babies if they are at high risk of becoming infected. However, these children may not have sufficient protection from this early dose, so they will still need the standard MMR doses at 12-13 months and 40 months of age.

The MMR vaccine is given as a single injection into the muscle of the thigh or upper arm.

Watch these healthtalk.org videos where parents weigh up the risks versus benefits of MMR vaccination.

MMR for older children

Children of any age up to 18 who missed, or only partially completed, their earlier MMR vaccination, can have a "catch-up" MMR vaccination on the NHS.

If you know, or suspect, your child hasn't been fully immunised, arrange with your GP for them to have a catch-up MMR vaccination,

MMR for women planning pregnancy

If you are a woman thinking about getting pregnant you may need MMR vaccination if you have low levels of rubella antibodies or you haven't had a rubella or MMR vaccination before.

Ask your GP to check if you're not sure whether you've had rubella or MMR before. They can arrange MMR vaccination to protect you against rubella.

Be aware that the MMR vaccination is not suitable for women who are already pregnant or who become pregnant soon after (within one month of) vaccination.

MMR for non-immune adults

The MMR vaccine can also be given on the NHS to adults who may need it, including people born between 1970 and 1979 who may have only been vaccinated against measles, as well as those born between 1980 and 1990 who may not be protected against mumps.

Check with your GP if you're not sure whether you've had MMR. If in doubt, go ahead and have the MMR vaccination. Even if you've had it before, it won't harm you to have a second or even third course of the vaccination.

Read more about when the MMR vaccine is needed.

How the MMR vaccine works

The MMR vaccine contains weakened versions of live measles, mumps and rubella viruses.

The vaccine works by triggering the immune system to produce antibodies against measles, mumps and rubella.

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

It's not possible for people who have recently had the vaccine to infect other people.

The MMR vaccine given in the UK is known under the brand names Priorix or MMRVAXPRO.

Does the MMR vaccine cause autism?

There has been some controversy about whether the MMR vaccine might cause autism, following a study published in 1998 by Dr Andrew Wakefield. In his paper published in The Lancet, Dr Wakefield claimed a link between the MMR vaccine and autism or bowel disease.

However, Andrew Wakefield's work has since been completely discredited and he has been struck off as a doctor in the UK. Subsequent studies during the last eight years have found no link between the MMR vaccine and autism or bowel disease.

Watch healthtalk.org videos where parents discuss their worries about the MMR vaccine.

Single measles, mumps and rubella vaccines

Single vaccines are not available on the NHS in the UK because there is a risk that fewer children would receive all the necessary injections, increasing the levels of measles, mumps and rubella in the UK.

The delay in having six separate injections would also put more children at risk of developing the conditions, as well as increasing the amount of work and inconvenience for parents and those administering the vaccines.

Side effects of MMR vaccine

As there are three separate vaccines within a single injection, different side effects can occur at different times. The side effects of the MMR vaccine are usually mild. It's important to remember that they're milder than the potential complications of measles, mumps and rubella.

Side effects include:

developing a mild form of measles that lasts for two to three days
developing a mild form of mumps that lasts for a day or two

In rare cases, a small rash of bruise-like spots may appear a number of weeks after the injection. See your GP if you notice this kind of rash, or if you have any concerns about your child's symptoms following the MMR.