New evidences show that Vitamin D actually helps against COVID19

Vitamin D has a well-characterised role in calcium and phosphate balance, affecting bone growth and turnover. Low vitamin D status is also associated with other non-communicable diseases and with increased susceptibility to infectious disease; notably, upper respiratory tract infections. However, whether low vitamin D levels are a cause or consequence of disease has remained a point of heated debate. Intervention trials have rarely shown benefits of vitamin D supplementation as treatments or preventive measures. However, one important exception to this general trend is for upper respiratory tract infections: a 2017 meta-analysis of individual patient data from 11 321 participants in 25 randomised controlled trials showed that vitamin D supplementation protected against acute respiratory tract infections and that patients with very low ( less than 25 nmol/L) serum 25-hydroxyvitamin D concentrations (a marker of vitamin D status) gained the most benefit.
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A growing body of circumstantial evidence now also specifically links outcomes of COVID-19 and vitamin D status. SARS-CoV-2, the virus responsible for COVID-19, emerged and started its spread in the Northern hemisphere at the end of 2019 (winter), when levels of 25-hydroxyvitamin D are at their nadir. Also, nations in the northern hemisphere have borne much of the burden of cases and mortality. In a cross-sectional analysis across Europe, COVID-19 mortality was significantly associated with vitamin D status in different populations. The low mortality rates in Nordic countries are exceptions to the trend towards poorer outcomes in more northerly latitudes, but populations in these countries are relatively vitamin D sufficient owing to widespread fortification of foods. Italy and Spain are also exceptions, but prevalence of vitamin D deficiency in these populations is surprisingly common. Additionally, black and minority ethnic people—who are more likely to have vitamin D deficiency because they have darker skin—seem to be worse affected than white people by COVID-19. For example, data from the UK Office for National Statistics shows that black people in England and Wales are more than four times more likely to die from COVID-19 than are white people.