Dr. Cole explained why Vitamin D deficiency is the biggest contributor to both Wuhan coronavirus hospitalizations and deaths: "Data shows what kills people. Cytokine storm. If you are in (Vitamin D) mid-level range, you will not die from COVID because you cannot get a cytokine storm."
According to Dr. Cole, widespread Vitamin D deficiency makes this a big problem. "Seventy to 80 percent of all Americans are immune suppressed because they are D deficient." He further noted that "96 percent of people in the ICU are Vitamin D deficient."
A short article and a video at; https://www.lifesitenews.com/news/our-greatest-weapon-against-the-coronavirus-is-vitamin-d-board-certified-pathologist
In December 2015 my blood Vitamin D level was low at 20, with a normal range of 30 to 100. I took 20,000IU a day for a month, then 10,000IU a day for three more months. Since then I take 5000IU one day and 10,000IU the next day. In 2018 my blood level was 95, with a normal range of 30 to 100. I haven't been checked since then.
In the United States, for an adult at or under 70 years of age, the recommended dietary daily allowance (RDA) for vitamin D is 600 IU. If you are over 70, the RDA for vitamin D is set at 800 IU.
From my experience you need as much as ten times that amount to have adequate Vitamin D in your body, especially if you do not get at least half an hour of sunshine a day. Or more if you work under the now old-fashioned tube lighting that is not full spectrum.
The risk of Vitamin D toxicity with high daily doses varies greatly with the source. Read these and others to make up your own mind;
https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
https://pubmed.ncbi.nlm.nih.gov/18290725/
https://bpspubs.onlinelibrary.wiley.com/doi/pdf/10.1111/bcp.13573
https://www.healthline.com/nutrition/how-much-vitamin-d-is-too-much
https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=19&contentid=VitaminD