Risk of Severe COVID-19 in Four Immunocompromised Populations: A French Expert Perspective.

Immunocompromised patients are disproportionately impacted by severe disease, hospitalization, and mortality associated with coronavirus disease 2019 (COVID-19). To optimize the management of these patients in clinical practice, we convened an expert panel to review current evidence on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine responses and severe COVID-19 in immunocompromised populations. We identified four main immunocompromised groups-solid organ transplant recipients, patients receiving allogeneic hematopoietic stem cell transplantation or chimeric antigen receptor (CAR) T cell therapy, patients treated for hematologic malignancies, and patients treated for inflammatory diseases-who mount suboptimal humoral responses to SARS-CoV-2 vaccination and are at increased risk of severe COVID-19-related outcomes. A wide range of risk factors were associated with reduced vaccine responses and/or poor outcomes, most commonly older age, comorbidities, and the type and number of immunosuppressive therapies. We believe that early identification and close monitoring of these at-risk patients, plus regular booster vaccinations, prophylactic monoclonal antibody therapy, non-pharmacologic prevention measures, prompt antiviral treatment, and other risk mitigation strategies, are critical to protect against SARS-CoV-2 infection and severe COVID-19.