Methods: Anti-spike IgG levels of 46 hospitalized patients with hematological and oncological diseases, measured between 21th December 2023 and 8th February 2024, were compared between subgroups of patients. Demographic data, underlying diseases, antineoplastic treatment, and the number of positive SARS-CoV-2 tests at the University Hospital Cologne were collected. Results: Patients with different diseases showed varying SARS-CoV-2 spike antibody levels. The highest levels were found in patients with diffuse large cell B-cell lymphoma (DLBCL) and acute leukemia who had not received specific treatment or had just initiated treatment, whereas the lowest levels were found in patients with DLBCL, acute leuke‑ mia, and multiple myeloma who had received at least one line of treatment. The geometric mean antibody titers were higher in female patients than in male patients and were highest in patients aged 41–50 years while lowest in those aged 61–70 years. Conclusion The data presented confirm broad variations in SARS-CoV-2 anti-spike IgG levels across patients with dif‑ ferent hematological and oncological diseases and highlight the complex interference of cancer biology, immune dysfunction, and treatment-related factors in shaping immune responses. Further research is needed to elucidate the mechanisms underlying these variations in antibody levels. We emphasize the need for regular booster vaccina‑ tions in this patient group.

Methods: Anti-spike IgG levels of 46 hospitalized patients with hematological and oncological diseases, measured between 21th December 2023 and 8th February 2024, were compared between subgroups of patients. Demographic data, underlying diseases, antineoplastic treatment, and the number of positive SARS-CoV-2 tests at the University Hospital Cologne were collected. Results: Patients with different diseases showed varying SARS-CoV-2 spike antibody levels. The highest levels were found in patients with diffuse large cell B-cell lymphoma (DLBCL) and acute leukemia who had not received specific treatment or had just initiated treatment, whereas the lowest levels were found in patients with DLBCL, acute leuke‑ mia, and multiple myeloma who had received at least one line of treatment. The geometric mean antibody titers were higher in female patients than in male patients and were highest in patients aged 41–50 years while lowest in those aged 61–70 years. Conclusion The data presented confirm broad variations in SARS-CoV-2 anti-spike IgG levels across patients with dif‑ ferent hematological and oncological diseases and highlight the complex interference of cancer biology, immune dysfunction, and treatment-related factors in shaping immune responses. Further research is needed to elucidate the mechanisms underlying these variations in antibody levels. We emphasize the need for regular booster vaccina‑ tions in this patient group.

Methods: Anti-spike IgG levels of 46 hospitalized patients with hematological and oncological diseases, measured between 21th December 2023 and 8th February 2024, were compared between subgroups of patients. Demographic data, underlying diseases, antineoplastic treatment, and the number of positive SARS-CoV-2 tests at the University Hospital Cologne were collected. Results: Patients with different diseases showed varying SARS-CoV-2 spike antibody levels. The highest levels were found in patients with diffuse large cell B-cell lymphoma (DLBCL) and acute leukemia who had not received specific treatment or had just initiated treatment, whereas the lowest levels were found in patients with DLBCL, acute leuke‑ mia, and multiple myeloma who had received at least one line of treatment. The geometric mean antibody titers were higher in female patients than in male patients and were highest in patients aged 41–50 years while lowest in those aged 61–70 years. Conclusion The data presented confirm broad variations in SARS-CoV-2 anti-spike IgG levels across patients with dif‑ ferent hematological and oncological diseases and highlight the complex interference of cancer biology, immune dysfunction, and treatment-related factors in shaping immune responses. Further research is needed to elucidate the mechanisms underlying these variations in antibody levels. We emphasize the need for regular booster vaccina‑ tions in this patient group.