Measles Home > MMR Warnings and Precautions

If you have a weakened immune system, your body may not respond fully to the MMR vaccine. Other warnings and precautions with MMR apply to people with epilepsy, tuberculosis, or an allergy to chicken eggs. In some cases, the vaccine should be avoided entirely. For example, people with leukemia, active tuberculosis, or any other serious illness should not get the vaccine.

What Should I Tell My Healthcare Provider Before Getting MMR?

Before you receive the MMR vaccine (officially known as M-M-R® II), talk to your healthcare provider if you have:
  • An immune-suppressing condition, such as HIV or AIDS, diabetes, or cancer
  • Had any sort of a reaction to a vaccine
  • A moderate or severe illness
  • Had a recent blood transfusion (or have recently received any other blood products)
  • Seizures or epilepsy
  • A low blood platelet count
  • Tuberculosis
  • A malignant blood or lymph disorder, such as leukemia or lymphoma
  • Any allergies, including to foods, dyes, or preservatives.
Also, let your healthcare provider know if you are:
  • Pregnant or thinking of becoming pregnant
  • Breastfeeding.
Make sure to tell the healthcare provider about any medications you are taking, including prescription and nonprescription medicines, vitamins, and herbal supplements.

Specific MMR Warnings and Precautions

Precautions and warnings to be aware of prior to receiving the MMR vaccine include the following:
  • You can receive MMR if you have a mild illness, such as the common cold. However, it is usually best to postpone the vaccine in the case of a moderate or severe illness.
  • Make sure your healthcare provider knows if you have ever had any serious reactions to any vaccines.
  • If you have an immune-suppressing condition, MMR may not be as effective as usual for protection against measles, mumps, or rubella, as your immune system may not be fully capable of responding to the vaccine.
More importantly, people with a weakened immune system may be more likely to actually get measles, mumps, or rubella from this vaccine, since it is a live vaccine. Severely immunocompromised individuals should not receive MMR.
  • MMR is considered a pregnancy Category C medication. This means it is unknown if it is safe for use during pregnancy (see MMR and Pregnancy).
  • It is not clear if MMR is safe for breastfeeding women (see MMR and Breastfeeding).
  • This vaccine is grown in chick embryo cell culture. If you are allergic to chicken eggs, your healthcare provider may want to take special precautions in case you have an allergic reaction. However, current recommendations suggest that people with chicken egg allergies should be able to safely receive this vaccine without any additional precautions.
  • Febrile seizures (seizures associated with high fevers in young children) have been associated with vaccines. If your child has a tendency to get febrile seizures, ask your healthcare provider if you should give an antifever medication such as acetaminophen (Tylenol®) or ibuprofen (Advil®, Motrin®) to help avoid this problem.
  • Caution should be used before giving this vaccine to people with a history of brain damage, seizures, or other conditions negatively affected by fevers, since MMR can cause fevers.
  • This vaccine can cause low blood platelets, which may increase the risk of bleeding. People who already have low blood platelets may be at a higher risk for severe problems.
  • The MMR vaccine should be postponed for at least three months if a person has received an immune globulin or a blood product, such as a blood transfusion, since such products reduce the effectiveness of MMR.
  • MMR does not contain thimerosal, a mercury-containing preservative. People who are concerned about exposure to this substance can be confident that this vaccine has no thimerosal -- not even trace amounts. Some people also are concerned about the aluminum content of vaccines. This vaccine contains no aluminum.
  • This vaccine contains animal and human fetal components. Specifically, parts of the vaccine are grown in chick embryo cells, fetal bovine (cow) serum, and a cell line developed from an aborted human fetus.
Written by/reviewed by:
Last reviewed by: Kristi Monson, PharmD;
Last updated/reviewed:
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