Fortunately, a few people were touting Vitamin D when the pandemic started (Mercola was one of them), and a few people listened (including yours truly). It sure beats the vaccines. From Dr. Joseph Mercola at lewrockwell.com:
At this point, there is simply no question that vitamin D optimization is a crucial component of COVID-19 prevention and treatment. In addition to the many studies published during 2020 and 2021, since December 2021, four large systematic meta-analyses1,2 have been published, looking at either vitamin D levels, supplementation or both.
In all cases, the data consistently show that low vitamin D levels raises your risk of COVID while higher baseline levels and/or supplementation lowers all risks by 1.5 to three times.
Therapeutic Role of Vitamin D in COVID
In the first of these four meta-analyses, “Prognostic and Therapeutic Role of Vitamin D in COVID-19: Systematic Review and Meta-Analysis,”3 published December 11, 2021, the researchers sought to determine “the association between vitamin D deficiency/insufficiency and susceptibility to COVID-19, its severity, mortality and role of vitamin D in its treatment.”
A total of 72 observational studies, covering 1,976,099 patients, met the criteria for inclusion. Compared to those with sufficient vitamin D, the odds of developing COVID-19 among those with deficient or insufficient vitamin D levels were 1.46 times higher.