The First Randomized Controlled Trial on Vitamin D and Covid-19
Noteworthy that this is in combination with anti-viral drugs at hospital admission: hydroxychloroquine (400 mg every 12 hours on the first day, and 200 mg every 12 hours for the following 5 days), azithromycin (500 mg orally for 5 days). Regardless, I'm going to assume this means being outside and getting sun is good for me.