MMR - Side effects of the MMR vaccine
NHS Choices Medical Reference
MMR contains three separate vaccines in one injection. Each vaccine can have different side effects that happen at different times:
- About one week to 10 days after the MMR injection, some children get a very mild form of measles. This includes a rash, high temperature, loss of appetite and general feeling of being unwell for about two or three days.
- About three to four weeks after the MMR injection, one in 50 children develops a mild form of mumps. This includes swelling of the glands in the cheek, neck or under the jaw. It lasts for a day or two.
- One to three weeks after receiving the rubella vaccine, some adult women experience painful, stiff or swollen joints, which lasts around three days.
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. If the child is treated quickly, they will recover fully. 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.