Study on Safety and Clinical Efficacy of AZVUDINE in COVID-19 Patients (SARS-CoV-2 Infected)

Hypothesis: AZVUDINE has therapeutic potential and safety profile for the treatment of patients infected with SARS-CoV-2. Goals: Primary objective • To assess the efficacy and safety of AZVUDINE (FNC) in relation to placebo, in patients infected with SARS-COV-2 in moderate to severe stage; Secondary objective • To evaluate the clinical outcome of the AZVUDINE group (FNC) compared to the placebo group in patients infected by SARS-COV-2 in moderate to severe stage; Pharmaceutical form of the experimental medicine: AZVUDINE 1 mg tablets Comparators: AZVUDINE placebo Statistical planning: The analyzes will be performed by FAS, PPS and SS and should be stratified by the severity of the disease (moderate, severe) and age (\<60 years, ≥ 60 years), to assess the following parameters: * Progression of the disease (moderate to severe, severe type); * Negative viral load conversion rate; * Time of negative conversion of viral load; * Temperature recovery time; * Time necessary to improve diarrhea, myalgia, fatigue, and other symptoms; * Time to improve the pulmonary image; * Frequency of supplemental oxygenation or non-invasive ventilation; * Frequency of AEs; * Mortality rate. All statistical tests will be bilateral tests. If the P value is ≤0.05, it is considered that there is statistical significance between the difference in the tests.