1. the need for non-invasive ventilation or high oxygen flow, or intubation of the trachea with artificial ventilation, or the use of vasopressors and/or extracorporeal membrane oxygenation at the time of assessment. 2. decompensation of concomitant pathology, whose severity exceeds the severity of covid-19 manifestations (for example, acute coronary syndrome, cerebral circulation disorders, acute surgical pathology requiring surgical intervention, bleeding independent of the localization, etc.). 3. topical or systemic use of methylene blue for any reasons at the time of evaluation or during the interval of 30 days before hospitalization. 4. known intolerance or hypersensitivity to methylene blue (indicated in the medical history of the patient). 5. patients with a high probability of not surviving within the first 24 h of hospitalization, regardless of the treatment, as defined by the investigator.

1. the need for non-invasive ventilation or high oxygen flow, or intubation of the trachea with artificial ventilation, or the use of vasopressors and/or extracorporeal membrane oxygenation at the time of assessment. 2. decompensation of concomitant pathology, whose severity exceeds the severity of covid-19 manifestations (for example, acute coronary syndrome, cerebral circulation disorders, acute surgical pathology requiring surgical intervention, bleeding independent of the localization, etc.). 3. topical or systemic use of methylene blue for any reasons at the time of evaluation or during the interval of 30 days before hospitalization. 4. known intolerance or hypersensitivity to methylene blue (indicated in the medical history of the patient). 5. patients with a high probability of not surviving within the first 24 h of hospitalization, regardless of the treatment, as defined by the investigator.

the need for non-invasive ventilation or high oxygen flow, or intubation of the trachea with artificial ventilation, or the use of vasopressors and/or extracorporeal membrane oxygenation at the time of assessment. decompensation of concomitant pathology, whose severity exceeds the severity of covid-19 manifestations (for example, acute coronary syndrome, cerebral circulation disorders, acute surgical pathology requiring surgical intervention, bleeding independent of the localization, etc.). topical or systemic use of methylene blue for any reasons at the time of evaluation or during the interval of 30 days before hospitalization. known intolerance or hypersensitivity to methylene blue (indicated in the medical history of the patient). patients with a high probability of not surviving within the first 24 h of hospitalization, regardless of the treatment, as defined by the investigator.

the need for non-invasive ventilation or high oxygen flow, or intubation of the trachea with artificial ventilation, or the use of vasopressors and/or extracorporeal membrane oxygenation at the time of assessment. decompensation of concomitant pathology, whose severity exceeds the severity of covid-19 manifestations (for example, acute coronary syndrome, cerebral circulation disorders, acute surgical pathology requiring surgical intervention, bleeding independent of the localization, etc.). topical or systemic use of methylene blue for any reasons at the time of evaluation or during the interval of 30 days before hospitalization. known intolerance or hypersensitivity to methylene blue (indicated in the medical history of the patient). patients with a high probability of not surviving within the first 24 h of hospitalization, regardless of the treatment, as defined by the investigator.

1. the need for non-invasive ventilation or high oxygen flow, or intubation of the trachea with artificial ventilation, or the use of vasopressors and/or extracorporeal membrane oxygenation at the time of assessment. 2. decompensation of concomitant pathology, whose severity exceeds the severity of covid-19 manifestations (for example, acute coronary syndrome, cerebral circulation disorders, acute surgical pathology requiring surgical intervention, bleeding independent of the localization, etc.). 3. topical or systemic use of methylene blue for any reasons at the time of evaluation or during the interval of 30 days before hospitalization. 4. known intolerance or hypersensitivity to methylene blue (indicated in the medical history of the patient). 5. patients with a high probability of not surviving within the first 24 h of hospitalization, regardless of the treatment, as defined by the investigator.

1. the need for non-invasive ventilation or high oxygen flow, or intubation of the trachea with artificial ventilation, or the use of vasopressors and/or extracorporeal membrane oxygenation at the time of assessment. 2. decompensation of concomitant pathology, whose severity exceeds the severity of covid-19 manifestations (for example, acute coronary syndrome, cerebral circulation disorders, acute surgical pathology requiring surgical intervention, bleeding independent of the localization, etc.). 3. topical or systemic use of methylene blue for any reasons at the time of evaluation or during the interval of 30 days before hospitalization. 4. known intolerance or hypersensitivity to methylene blue (indicated in the medical history of the patient). 5. patients with a high probability of not surviving within the first 24 h of hospitalization, regardless of the treatment, as defined by the investigator.