Evaluation of the efficacy and safety of Melatonin in moderately ill patients with COVID-19: A structured summary of a study protocol for a randomized controlled trial oleh Ava Ziaei, Parivash Davoodian, Habib Dadvand, Omid Safa, Soheil Hassanipour, Mahmoud Omidi, Moein Masjedi, Fahime Mahmoudikia, Bahareh Rafiee, Mohammad Fathalipour