Hi @bobala, Hematologists are specilists who focus on blood disorders, including anemia, clotting disorders, and blood cancers like leukemia and lymphoma. It’s not uncommon for hematologists to hold a dual certification in oncology. Either way, your hematologist (or NP in the office) would be the person ask about the MMR vaccine and if it’s reasonable for you to have the vaccination. There are two injections at least 28 days apart.