I echo Sandy's comments 100%.
Additional research is showing T-cell activation and cytokine 'storm' control is maximized at blood levels over 50 ng/ml (but less than 100 ng/ml). Keeping your D level over 50 ng/ml will help protect against virus attack.
Also - for cancer, the ideal level is around 70 ng/ml, which is where I try to keep mine as an upper limit. I achieve this easily in summer, but during winter - even with 10,000 IU's D3 supplementation, my level will fall towards 50 ng/ml. I test my vitamin D status twice per year. I consider testing for vitamin D as important as PCR testing for CML.
Regarding supplementation - I would avoid taking anymore than 10,000 IU's per day (D3) in order to avoid overdosing. Also, by taking vitamin K2 (200 mcg) per day with D3, chances of overdosing is greatly reduced. K2 uses D to carboxylate Calcium in order to remove it from soft tissue and place in bone. D3 + K2 are a "dynamic' duo. Both are fat soluble.
Also - for those who take Curcumin (may need a separate thread?):
Lecithin taken with Curcumin enhances Curcumin's anti-inflammatory effect. As many may know, it is the inflammatory response to Covid-19 infectioni which is dangerous (floods the lungs leading to hypoxia). Coupling D3 with Curcumin (w/Lecithin) may very well provide added protection so that even if you were to get exposed to the virus, you may never experience symptoms or get very sick.
(note: since I have raised my D level to where it is now, I have not had a cold, flu or other respiratory 'anything' despite being sneezed on or around sick people for over 10 years.)
(on a personal note, I will be diving in the Bahamas this week! and expect to get plenty of sun. I won't be taking any D3 during this time - expecting my skin to produce plenty of it on its own)