The MMR vaccine protects against measles, mumps, and rubella (German measles). These diseases can be extremely serious. Before vaccinations were available, many children died from them. If people stop getting vaccinated, the diseases could come back.
Serious complications of measles include:
- brain damage
Serious complications of mumps include:
- meningitis, an infection of the brain or covering of the spinal cord
- swelling of the reproductive organs (orchitis)
- sterility (rare)
Serious complications of rubella mostly affect pregnant women. They include miscarriage and birth defects.
Children need two doses of the MMR vaccine for protection. The first is usually given between the ages of 12 and 15 months. The second is given when children are 4 to 6 years old. However, the second dose can be given as soon as 28 days after the first.
Anyone born after 1956 who wasn’t vaccinated as a child, should get at least one dose of MMR as an adult. The only exception would be individuals who have had all three diseases.
The MMRV vaccine combines the MMR and varicella vaccines. Therefore, it also protects against chickenpox. However, the risk of side effects is higher than with separate shots. This is true even if the shots are given at the same visit.
Certain people should not get the MMR vaccine. This includes anyone who:
- is allergic to the antibiotic neomycin
- is allergic to another component of the vaccine
- has had a serious reaction to a previous dose of MMR or MMRV
People with immune system deficiencies should talk to their doctors about the risks of vaccination. They may want to skip the vaccine.
In addition, certain people may want to delay vaccination. This includes people who:
- have recently received a blood transfusion
- have been vaccinated within the previous four weeks
- are pregnant
- are currently moderately to severely ill
Serious side effects from the MMR vaccine are extremely rare. Most people who receive the vaccine have no side effects. When side effects do occur, they are usually mild. They include:
- fever (common)
- mild rash (common)
- swollen glands
- joint pain or stiffness (common)
- serious allergic reactions (very rare)
There is no evidence that getting three separate vaccines is safer than getting the combined vaccine.