What follows is from an open letter from scientists to Governments of the World. Let me make a prediction: Governments will ignore this sound, non-patentable health advice.
There is no need to wait for further clinical trials to increase use of something so safe, especially when remedying high rates of deficiency/insufficiency should already be a priority.
Therefore, we call on all governments, doctors, and healthcare workers worldwide to immediately recommend and implement efforts appropriate to their adult populations to increase vitamin D, at least until the end of the pandemic. Specifically to:
Recommend amounts from all sources sufficient to achieve 25(OH)D serum levels over 30ng/ml (75nmol/L), a widely endorsed minimum with evidence of reduced COVID-19 risk.
Recommend to adults vitamin D intake of 4000 IU (100mcg) daily (or at least 2000 IU) in the absence of testing. 4000 IU is widely regarded as safe.5
Recommend that adults at increased risk of deficiency due to excess weight, dark skin, or living in care homes may need higher intakes (eg, 2x). Testing can help to avoid levels too low or high.
Recommend that adults not already receiving the above amounts get 10,000 IU (250mcg) daily for 2-3 weeks (or until achieving 30ng/ml if testing), followed by the daily amount above. This practice is widely regarded as safe. The body can synthesize more than this from sunlight under the right conditions (e.g., a summer day at the beach). Also, the NAM (US) and EFSA (Europe) both label this a “No Observed Adverse Effect Level” even as a daily maintenance intake.
Measure 25(OH)D levels of all hospitalized COVID-19 patients & treat w/ calcifediol or D3, to at least remedy insufficiency <30ng/ml (75nmol/L), possibly with a protocol along the lines of Castillo et al ‘20 or Rastogi et al '20, until evidence supports a better protocol.
Many factors are known to predispose individuals to higher risk from exposure to SARS-CoV-2, such as age, being male, comorbidities, etc., but inadequate vitamin D is by far the most easily and quickly modifiable risk factor with abundant evidence to support a large effect. Vitamin D is inexpensive and has negligible risk compared to the considerable risk of COVID-19.
Please Act Immediately
You can read the entire Open Letter here:
Vitamin D is cheap and very safe for adults and children:
Take 1-2 tablets per day with 1-2 per day of these:
There is no need for a healthy person to take more. Small amounts of a nutrient most days are always better than big, infrequent doses. There is probably no need to take supplementary vitamin D on days you get some sun on your torso.