Maybe not for Covid specifically, but they have found it helps with other respiratory diseases. Example: https://news.harvard.edu/gazette/story/2017/02/study-c

Maybe not for Covid specifically, but they have found it helps with other respiratory diseases. Example: https://news.harvard.edu/gazette/story/2017/02/study-confirms-vitamin-d-protects-against-cold-and-flu/ https://news.harvard.edu/gazette/story/2017/02/study-confirm... I take 2000 IU every day and have for years. My doctor said my vitamin D levels were low, but they are now in normal range.