Patients with cancer whose immune systems are being supported or rebuilt by bone marrow transplantation should begin receiving vaccines for protection against SARS-CoV-2 three months post-transplant, according to a large, prospective, observational study led collaboratively by the Center for International Blood and Marrow Transplant Research, the Blood & Marrow Transplant Clinical Trials Network and Fred Hutchinson Cancer Center. The research, involving 22 cancer centers and research institutions in the United States and focusing on mRNA-based vaccines, published in The Lancet journal eClinicalMedicine.