I take 5,000IU/day of vitamin D3. My doctor has recommended this high dosage because of my MS. People shouldn't just take this much without checking first with their doctors, I'm sure.
Here is what the AARP has to say on this topic (May 6)--"Vitamin D and COVID-19: What the Doctors Know (and Don't Know) So Far":
The Latest Research on Vitamin D and COVID-19 Prevention