Thanks for sharing your experience, Marijke. Blood tests for serum concentration of 25OHD are quite common and not costly anymore. If you have a chance to test your level with your next blood test, why not include it. As I mentioned in my response to Georgios' question, if you find your levels to be >20ng/ml you should be fine.

And, yes, Vit-D had another 10 minutes of fame during COVID (as you mentioned, like many other things). I don't buy it, because all the studies were produced in a hurry and were association studies mostly (not proving causality). In fact, within 4 years, about 2 million scientists published more than half a million papers on COVID. The temptation to become a patronizing epidemiologist was apparently too big. In self-criticism: even our team published on COVID, but we are dealing with professonal athletes wnd we wanted to compare the return-to-duty fitness between COVID-exposed and unexposed athletes. So, there is some justification there, but the temptation was indeed great.