Yeah, and Italy, Spain, and France are some of the sunnier countries in Europe (compared to Germany, UK, Belgium, Scandinavia, etc). If anything I would expect vitamin D deficiency to be less common there.
Diet seems to be the issue.
Don't forget Ecuador which is literally on the equator and experiencing a major outbreak.
It's the wet season in Ecuador
I don't know about Spain, but in both Italy and France the regions most affected are the northern overcast places. The impact around the Med is much smaller, despite much much more retirees