the number of patients recruited was not reached because covid cases were low

This is a prospective, multicenter, randomized (3:1), placebo- controlled, parallel-group, double-blind trial.

Patients will be randomized into two arms of treatment:

• Placebo + SoC (N=30)
• NanoManganese® + SoC (N=90)

Patients will be treated and followed-up for 10 days:

• Arterial oxygen partial pressure (PaO2) will be measured at baseline and at days 3, 5 and 10,
• Oxygen saturation, vital signs including respiration rate, pulse rate, blood pressure and body temperature, disease severity (7-point ordinal scale and NEWS2 score) will be measured at baseline and daily,
• Hematology and biochemistry measurements will be done at baseline and at day 3, 5 and 10,
• Pharmacokinetic (Blood Mn concentration) measurements will be done at baseline and at day 3, 5 and 10,
• Biomarkers will be measured at baseline and at day 3, 5 and 10. At the end of the 10-day treatment period, a follow-up visit will be planned between day 15 and day 22. The following.

assessments/examinations will be performed: oxygen saturation, vital signs including respiration rate and body temperature, disease severity (7-point ordinal scale and NEWS2 score), electrocardiogram (ECG), hematology, biochemistry, concomitant therapies, and adverse events.

120 patients will be enrolled in this study, they will be randomly assigned in 2 arms on a 3:1 ratio, 90 patients in the NanoManganese®

+ Standard of Care group and 30 patients in the placebo + Standard of Care group.

This study will be conducted in Brazil and will be conducted in around 8 investigational sites

The investigational products are :

Manganese sulfate monohydrate, MnSO4, H2O (NanoManganese®) will be administered using the microemulsion AONYS® technology. The product is mucoadhesive, it sticks to the mucosa of the cheeks on which it will be deposited and will not be swallowed.

The placebo (Pharmacopoeia soybean oil) will be administered using the same protocol and the same bottle.

Treatments :

NanoManganese® + standard of care group:

• NanoManganese®: administration of 2 mL twice a day (morning and evening) by depositing 1 mL in the gingivo-jugal groove of each cheek with the graduated pipette.
• Standard of care

Placebo + standard of care group:

• Placebo: administration of 2 mL twice a day (morning and evening) by depositing 1 mL in the gingivo-jugal groove of each cheek with the graduated pipette.
• Standard of care The treatments will be administered by the nurse. Duration of treatment: 10 days or until hospital discharge or until death.

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)