Not worried about covid, was working on health before the China flu.

Yes. Pro tip, gradually go from 1 a day in morning to 5 (I bought the big bottle from Costco, very reasonable). They call it a vitamin but it’s more of a hormone precursor and it’s vital to multiple processes. Northern hemisphere, winter, very little skin expose to sunlight— unless you’re eating like an Inuit or Viking it’s a safe bet you should supplement. Your doctor will gladly run d level as part of annual blood work at probably 0 cost.