Low Serological Prevalence of SARS-CoV-2 Antibodies in Cancer Patients at a German University Oncology Center

Background: Coronavirus disease 2019 (COVID-19) cases in Germany, as in most other places in Europe or worldwide, are still highly prevalent. Vaccination rates currently remain low, putting cancer patients at a continued risk of infection with SARS-CoV-2, while prevalence of SARS-CoV-2 antibodies among cancer patients in Germany remains essentially unknown. Methods: Between August 2020 and February 2021, patients admitted to our hospital were prospectively enrolled in our COVID-19 biobank. Collected sera were analyzed for SARS-CoV-2-IgM/IgG using Elecsys Anti-SARS-CoV-2 assay. Results: One hundred and ten patients with cancer were included in this study. With 71 (65%) patients, most had active cancer treatment, mainly chemotherapy (56%). The most frequent diagnosis was gastrointestinal cancer (54%) with pancreatic cancer being the most common cancer type (24%). Hematologic malignancies were present in 21 patients (17%). Among the cancer patients first diagnosed during the pandemic, the rate of palliative treatment situations tended to be higher (76% vs. 67%, p = 0.17). A history of SARS-CoV-2 infection was documented in 15 (14%) patients; however, SARS-CoV-2 antibodies were detected in 10 (67%) patients only. Of the patients without a history of SARS-CoV-2 infection, none displayed SARS-CoV-2 antibodies. Conclusion: In the present single-center experience, a low serological prevalence of SARS-CoV- 2 antibodies among cancer patients even after SARS-CoV-2 infection was found. The results support continued strict preventive measures as well as efforts toward faster vaccination, due to a low immunity level in the population. (C) 2021 S. Karger AG, Basel