GEO-CM04S1 vs mRNA SARS-COV-2 Vaccine

This phase 2 trial studies the immune response to GEO-CM04S1 (previously designated as COH04S1) compared to standard of care (SOC) mRNA SARS-COV-2 vaccine in patients with blood cancer who have received stem cell transplant or cellular therapy. GEO-CM04S1 belongs to a category called modified vaccinia Ankara (MVA) vaccines, created from a new version of MVA, called synthetic MVA. GEO-CM04S1 works by inducing immunity (the ability to recognize and fight against an infection) to SARS-CoV-2. The immune system is stimulated to produce antibodies against SARS-CoV-2 that would block the virus from entering healthy cells. The immune system also grows new disease fighting T cells that can recognize and destroy infected cells. Giving GEO-CM04S1 after cellular therapy may work better in reducing the chances of contracting coronavirus disease 2019 (COVID-19) or developing a severe form of COVID-19 disease in patients with blood cancer compared to SOC mRNA SARS-CoV-2 vaccine.