2021 Update of AGIHO guideline on evidence-based management of COVID-19 in cancer patients regarding diagnostics, viral shedding, vaccination and therapy - Giesen, N; Sprute, R; Rüthrich, M; for the COVID-19 guideline panel of the Infectious Diseases Working Party (AGIHO) of the German Society for Haematology and Medical Oncology (DGHO) (Eur J Cancer, 2021)