- Pregnant and/or lactating women - Prior diagnosis of vitamin D deficiency (less than 20 ng/mL) - Being on vitamin D supplementation greater than 1000 IU/day within past 3 months: - Organ failure/ need for ICU stay/ organ support at the time of enrollment - Patients with any disorder related to calcium metabolism that in the opinion of the investigator does not justify a high dose of vitamin D - Patients who have been already enrolled in any other clinical trial

- Pregnant and/or lactating women - Prior diagnosis of vitamin D deficiency (less than 20 ng/mL) - Being on vitamin D supplementation greater than 1000 IU/day within past 3 months: - Organ failure/ need for ICU stay/ organ support at the time of enrollment - Patients with any disorder related to calcium metabolism that in the opinion of the investigator does not justify a high dose of vitamin D - Patients who have been already enrolled in any other clinical trial