Patient is ≥ 18 years of age, diagnosed with COVID-19 based on a positive PCR or antigen test. Hospitalized. AND one of immunocompromised conditions/treatments below B-cell inhibition related ICP Use of anti-CD19 or -CD20 directed antibody therapy in 6 months prior to inclusion. Previous or current treatment with drugs that significantly impair B cell function (e.g. ibrutinib, venetoclax, acalabrutinib, idelalisib etc) within 6 months prior to inclusion Other immunosuppression/treatment related ICP Patients treated with bendamustine, purine analogues or anti-thymocyte globulin within 6 months prior to inclusion. Solid organ transplant patients that are taking systemic immunosuppressive drugs from at least three pharmacological classes. Cellular therapy related ICP Allogeneic hematopoietic stem cell transplant (HSCT) in 12 months prior to inclusion. HSCT for which systemic therapy against graft-versus-host-disease is used. Recipient of CAR-T cells < 2 years prior to inclusion. Disease related ICP Chronic B-cell leukemia´s: CLL, HCL, PLL, multiple myeloma, Waldenströms macroglobulinemia Congenital ICP Congenital disorder resulting in severe B-cell dysfunction or depletion requiring immunoglobulin suppletion (e.g. agammaglobulinemia).

Patient is ≥ 18 years of age, diagnosed with COVID-19 based on a positive PCR or antigen test. Hospitalized. AND one of immunocompromised conditions/treatments below B-cell inhibition related ICP Use of anti-CD19 or -CD20 directed antibody therapy in 6 months prior to inclusion. Previous or current treatment with drugs that significantly impair B cell function (e.g. ibrutinib, venetoclax, acalabrutinib, idelalisib etc) within 6 months prior to inclusion Other immunosuppression/treatment related ICP Patients treated with bendamustine, purine analogues or anti-thymocyte globulin within 6 months prior to inclusion. Solid organ transplant patients that are taking systemic immunosuppressive drugs from at least three pharmacological classes. Cellular therapy related ICP Allogeneic hematopoietic stem cell transplant (HSCT) in 12 months prior to inclusion. HSCT for which systemic therapy against graft-versus-host-disease is used. Recipient of CAR-T cells < 2 years prior to inclusion. Disease related ICP Chronic B-cell leukemia´s: CLL, HCL, PLL, multiple myeloma, Waldenströms macroglobulinemia Congenital ICP Congenital disorder resulting in severe B-cell dysfunction or depletion requiring immunoglobulin suppletion (e.g. agammaglobulinemia).