The dilemma of COVID-19 recurrence after clinical recovery. Issue 6 (December 2020) - Bongiovanni, Marco; Vignati, Marco; Giuliani, Giuseppe; Manes, Giampiero; Arienti, Stefania; Pelucchi, Loris; Cattaneo, Nicoletta; Bodini, Bruno Dino; Clerici, Danila; Rosa, Fabio; Pellegrini, Lucienne; Schettino, Mario; et al.