Mild or intermediate reactions to MMR

Most children who have the MMR vaccine do not have any problems with it or if reactions do occur they are usually mild. (See 'No reactions to MMR'.) The risk of the MMR vaccine causing serious harm, or death, is extremely small.

The overwhelming majority of parents believe in immunisation for their children. We have however included here the views of a few parents who do not believe immunisation is right for their own child based on their personal beliefs. Their views represent a small proportion of the population.

The most likely reactions after having the MMR vaccine are mild symptoms that are like the diseases that the immunisations protect children from, such as a mild rash, and a mild fever. They usually last for a short duration and are not infectious to others.

Mild reactions such as fever (up to 1 person out of 6), mild rash (about 1 person out of 20 can occur. If these problems occur, it is usually within 7-12 days after the injection. Swelling of the glands in the cheeks or neck can also occur two to three weeks after the injection but it is rare. 

Intermediate reactions can occur such as a febrile convulsion (a fit) (about 1 out of 3,000 doses), a febrile fit can happen with a fever from any cause and is treated by keeping the child cool, temporary low platelet count, which can cause a bleeding disorder (about 1 out of 30,000 doses) if this occurs seek hospital specialist advice.  

A small number of parents we interviewed mentioned that their child had a small swelling where the injection was given that had disappeared quickly. One mother said her son had a mild rash during the week after his MMR vaccine, which went after twenty-four hours.   

A couple of mothers recalled that their daughters had been irritable or down in the dumps for a few days, which had worried them at first. But these reactions had passed and they had returned to being their normal selves.

We did not interview any parent whose child had an intermediate reaction to the MMR vaccine as listed above.  

One mother we interviewed talked about the unusually strong local reaction her children had after the second dose of MMR. This reaction was extremely rare. In her son's case, swelling which started in the arm where the injection was given spread across his chest and he had to be in hospital on antibiotics for three days.


Last reviewed October 2015
Last updated October 2015



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