> The difference is that it's almost certainly not going to harm someone to wear a mask, whereas recommending vitamin D supplements to everyone might.

Vitamin-D supplementation is considered safe and is already recommended to everyone by health authorities, at least seasonally, not specifically for COVID-19 related reasons. That's just not part of the media spectacle, but it think it should be.

There were lots of arguments against masks in the beginning, such as people becoming more careless due to feeling "protected". It's a valid argument to make, but you couldn't make it anymore today, "masks are good" is dogma.

Obviously, Vitamin D is not a miracle cure, but there's mounting evidence that it may be beneficial, just like masks, perhaps even drastically more so. I don't accept the "we need to wait for more evidence" argument anymore when I'm simultaneously forced by law to wrap a piece of cloth against my mouth/noise, based on similarly poor evidence.