Challenges, strategies and consequences from the perspective of German nursing home managers during the first wave of the COVID-19 pandemic - a qualitative interview study oleh Marco Sander, Richard Dano, Anja Bieber, Anna Dammermann, Steffen Fleischer, Claudia Dinand, Martin Müller, Ralph Möhler, Kristin Schultes, Sascha Köpke, Martin N. Dichter, on behalf of the HEICO-study group