Non-infected with COVID-19 (based on WHO criteria) Older than 17 years old and younger than 76 years old No medications or disorders that would affect vitamin D metabolism Women must be not pregnant at baseline and during study Ability and willingness to give informed consent and comply with protocol requirements

Non-infected with COVID-19 (based on WHO criteria) Older than 17 years old and younger than 76 years old No medications or disorders that would affect vitamin D metabolism Women must be not pregnant at baseline and during study Ability and willingness to give informed consent and comply with protocol requirements