On: Over 80% of Covid-19 patients in a hospital study ...

[outside1234]

Could this be simply because they have been trapped inside in bed (not getting sunlight)?

[djsumdog → outside1234]

Vitamin D doesn't go up or down in a few days. It's a cumulative thing.

[beagle3 → djsumdog]

Studies show that a Month after a megadose of 60,000IU blood levels revert to base level, - so it does, in fact, change significantly over a few days.

Furthermore, it’s possibly the body uses more for some processes when in distress, which would complicate reasoning.