Changes in emergency department utilisation in Germany before and during different phases of the COVID-19 pandemic, using data from a national surveillance system up to June 2021 oleh Madlen Schranz, T. Sonia Boender, Timo Greiner, Theresa Kocher, Birte Wagner, Felix Greiner, Jonas Bienzeisler, Michaela Diercke, Linus Grabenhenrich, AKTIN-Research Group, Annette Aigner, Alexander Ullrich