- <18 years old; - women in childbearing age; - >= 72 hs since current admission; - requirement for high dose of oxygen (>5 liters/minute) or mechanical ventilation (non-invasive or invasive); - history of chronic kidney disease requiring hemodialysis or chronic liver failure; - inability for oral intake; - previous treatment with pharmacological vitamin d; - history of: - previous treatment with anticonvulsants; - sarcoidosis; - malabsorption syndrome; - known hypercalcemia. - life expectancy less than 6 months; - known allergy to the study medication; - any condition impeding to bring informed consent.

- <18 years old; - women in childbearing age; - >= 72 hs since current admission; - requirement for high dose of oxygen (>5 liters/minute) or mechanical ventilation (non-invasive or invasive); - history of chronic kidney disease requiring hemodialysis or chronic liver failure; - inability for oral intake; - previous treatment with pharmacological vitamin d; - history of: - previous treatment with anticonvulsants; - sarcoidosis; - malabsorption syndrome; - known hypercalcemia. - life expectancy less than 6 months; - known allergy to the study medication; - any condition impeding to bring informed consent.

- <18 years old; - women in childbearing age; - requirement for high dose of oxygen (>5 liters/minute) or mechanical ventilation (non-invasive or invasive); - history of chronic kidney disease requiring hemodialysis or chronic liver failure; - unavailability to oral intake; - previous treatment with pharmacological vitamin d; - history of: - previous treatment with anticonvulsants; - sarcoidosis; - malabsorption syndrome; - known hypercalcemia. - life expectancy less than 6 months; - known allergy to the study medication; - any condition impeding to bring informed consent.

- <18 years old; - women in childbearing age; - requirement for high dose of oxygen (>5 liters/minute) or mechanical ventilation (non-invasive or invasive); - history of chronic kidney disease requiring hemodialysis or chronic liver failure; - unavailability to oral intake; - previous treatment with pharmacological vitamin d; - history of: - previous treatment with anticonvulsants; - sarcoidosis; - malabsorption syndrome; - known hypercalcemia. - life expectancy less than 6 months; - known allergy to the study medication; - any condition impeding to bring informed consent.