Patients with multiple myeloma infected with COVID-19 during autologous stem cell transplantation.

Despite the global vaccination campaigns, certain patient groups remain highly vulnerable to SARS-CoV-2 and are at high risk for unfavorable COVID-19 outcomes. As previously shown by our group and a more recent report by Chang Su and coworkers, patients with multiple myeloma (MM) undergoing autologous stem cell transplantation (ASCT) represent one of such high-risk populations. This is due to the underlying disease-related immunodeficiency, suboptimal response to vaccines, heavy exposure to dexamethasone, and the use of high-dose melphalan prior to the ASCT procedure. Contracting SARS-CoV-2 and developing COVID-19 during the ASCT procedure remain high-risk events for these patients. It is then crucial to maintain and implement all appropriate strategies to prevent COVID-19 breakthroughs in this clinical setting. This might include targeted pre- and post-exposure prophylaxis with monoclonal antibodies, based on the circulation and prevalence of different SARS-CoV-2 variants/subvariants, and the prompt use of antivirals if, despite prophylaxis, MM patients develop COVID-19 during the transplantation procedure. We emphasize the importance of regularly monitoring MM patients for SARS-CoV-2 infection at all stages of the ASCT procedure. This is crucial to promptly implement measures to reduce the risk of unfavorable COVID-19 outcomes during the current post-pandemic phase.