Wife and I take about 5000iu a day (sometimes more in the winter) along with vitamin K2. K2 doesn't have much to do with covid that I know of but it is important to keep calcium going where it is supposed to go (bones) and away from where it is not supposed to go (circulatory system). D3 and K2 work together for calcium management. But I digress, different subject than covid. https://www.amazon.com/gp/product/B07RX4P4RL/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1 https://www.amazon.com/gp/product/B06Y3X5SDZ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 John | 
I guess if you live in the USA take vitamin D3
