Contraindications and Precautions of MMR Vaccine Contraindications for the MMR vaccine include A severe allergic reaction (eg, anaphylaxis) after a previous dose or to a vaccine component, including neomycin Known severe primary or acquired immunodeficiency (eg, due to leukemia, lymphomas, solid tumors, tumors that affect bone marrow or the lymphatic system, AIDS, severe HIV infection, treatment with chemotherapy, or long-term use of immunosuppressants) Pregnancy (vaccination is postponed until pregnancy is completed) Family history of first-degree relatives (parents or siblings) with congenital hereditary immunodeficiency, unless the vaccine recipient is known to be immunocompetent HIV infection is a contraindication only if immunocompromise is severe (CDC immunologic category 3 with CD4 < 15% or CD4 count < 200 cells / mcL); if immunocompromise is not severe, risks of wild measles outweigh risk of acquiring measles from the live vaccine.