The link works for me kiwi? Can vitamin D really prevent Covid-19? Here's what the evidence says.

As an FYI Vit D3 is something that even many of the hospitals here are giving COVID patients, and although CDC/NIH is still doing research for statistically significant cases, it does seem to have a protective effect from severe COVID illness, albeit not necessarily preventing COVID (at least not enough evidence for that claim yet)

Supplementing with D3 also has other important health benefits, especially as our bodies don't make enough in our modern world where most don't spend enough healthy outdoor time.
My own doctor has had me on D3 for years, and my son has directly seen it's benefit in alleviating Crohn's symptoms.