Scientists at Israel’s Bar-Ilan University have identified low plasma vitamin D level to be an independent risk factor for COVID-19 infection and hospitalization. They studied 782 Israeli COVID-19 positive patients and 7,807 COVID-19 negative patients.

https://www.i24news.tv/en/news/international/1595758992-lack-of-vitamin-d-could-make-you-more-vulnerable-to-coronavirus-researchers