A Vaccine Booster (GEO-CM04S1) for the Prevention of COVID-19 in Patients With Chronic Lymphocytic Leukemia

This phase II trial compares the effect of the GEO-CM04S1 vaccine with the current standard of care vaccine in preventing COVID-19 infections in patients with chronic lymphocytic leukemia (CLL). The GEO-CM04S1 vaccine uses a modified vaccinia virus (MVA) backbone that may be more effective at boosting COVID-19 immunity in patients with poor immune responses. MVA strongly induces T cell expansion (infection fighting blood cells) even in the background of a suppressed immune system, which is the case in the targeted CLL patient population. Using the GEO-CM04S1 vaccine may be more effective at preventing COVID-19 infection in patients diagnosed with CLL.