NanoMn®_COVID-19 A Prospective, Multicenter, Randomized, Placebo-controlled, Parallel-group, Double-blind Trial to Evaluate the Clinical Efficacy of NanoManganese® on Top of Standard of Care, in Adult Patients With Moderate to Severe Coronavirus Disease 2019 (COVID-19)

Inclusion Criteria: * Male and female patient aged ≥ 18 years * Patient hospitalized with positive COVID-19, confirmed by a Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) or an antigen test done ≤ 7 days before study entry * Patient with at least 1 of the National Institutes of Health COVID- 19 clinical symptoms (Fever or chills, Cough, Shortness of breath or difficulty breathing, Fatigue, Muscle or body aches, Headache, New loss of taste or smell, Sore throat, Congestion or runny nose, Nausea or vomiting, Diarrhea) that appeared ≤ 15 days before study entry * Patient with a peripheral capillary oxygen saturation (SpO2) \< 96%, or with an arterial oxygen partial pressure (PaO2) ≤65 mmHg, at study entry * Female patient of childbearing potential must be willing to use an efficient birth control method during the study and until 3 months after IMP administration. A woman is considered to be of childbearing potential if she is post menarche, has not reached a postmenopausal state (≥ 12 continuous months of amenorrhea with no identified cause other than menopause), and has not undergone surgical sterilization (removal of ovaries and/or uterus, tubal ligation). The following are acceptable contraceptive methods: - Established use of oral, injected, or implanted hormonal methods of contraception - Intrauterine system or placement of an intrauterine device - Double barrier methods of contraception: condom or occlusive cap (diaphragm or cervical/vault caps) with spermicidal foam, gel, film, cream, or suppository - True abstinence \[periodic abstinence (e.g., calendar, ovulation, symptothermal, post ovulation methods) and withdrawal are not acceptable methods of contraception\] * Male patient must be willing to use male contraception (condom) during the study, avoid donating semen during study and until 3 months after last dose of IMP administration. * Patient must sign the informed consent form * Patient who have or have not been vaccinated for COVID-19 (1, 2, 3 or 4 shots) can enter the study Exclusion Criteria: * Refusal to participate expressed by patient * Pregnancy or breast-feeding * Anticipated transfer to another hospital, which is not a study site within 72 hours * Contraindication to Manganese supplementation * Patient under Long-term oxygen therapy or invasive ventilation prior to COVID-19 infection * Patient requiring Continuous Positive Airway Pressure (CPAP), high flow, or Non-Invasive Ventilation (NIV) and a SpO2 \<92% * Patient on invasive mechanical ventilation * Patient with homozygotic sickle cell disease or methemoglobin. * Patient receiving a biotherapy as a SoC for COVID-19 * Patient participating in another drug trial * Patient under guardianship or prisoner * Patient with a written order for restricted care * Patient allergic to peanut or soja * Patient under parenteral nutrition (with Mn in composition)