Tocilizumab's efficacy in patients with Coronavirus Disease 2019 (COVID‐19) is determined by the presence of cytokine storm. Issue 1 (29th June 2020) - Andrianopoulos, Ioannis; Papathanasiou, Athanasios; Papathanakos, Georgios; Chaidos, Aristeidis; Koulouras, Vasilios