Covid-19 deaths and Vitamin D: the facts.
11th May 2020

Covid-19 is a serious pandemic There have been more than 4 million cases worldwide and more than 280,000 deaths. In the UK there have been more than 215,000 confirmed cases and 31,500 deaths.

In the UK, people of black African and Asian ethnicity (BAME) have experienced a much greater risk of Covid-19 deaths than those with white skins. 26 doctors have died from Covid-19 the UK and 25 were BAME but not socio-economically disadvantaged. Dark skins are less efficient at producing vitamin D and the well-known fact that deficiency of vitamin D is common in BAME people is one obvious reason why they are particularly at risk of serious illness from Covid-19.

Vitamin D activates the immune system cells, the T-lymphocytes and macrophages. This process requires a reservoir of vitamin D stores to meet the needs for sudden high demands in activating defensive immunity in response to infection.

Are we deficient? Most likely although most people will be unaware; and when our stores are low, our immune system is not in best working order. The average UK vitamin D blood level is 15 ng/ml, experts recommend to have levels above 40 ng/ml (100 nmol/l)

In Indonesia, a study has shown a death rates of 4.1% in Covid-19 patients with ideal blood levels of vitamin D, [greater than 30ng/ml] of 86.8% in those with moderate deficiency, and of 98.9% in those with severe deficiency.

In the Philippines, 85% of Covid-19 patients hospitalized with ideal blood levels of vitamin D had mild disease, with a 15% chance of developing moderate, severe, or critical disease. Those with very low levels of vitamin D had an 80% chance of developing severe or critical disease.

In India, 85% patients with severe Covid-19 infection had vitamin D deficiency.

In Belgium it has been found that men with severe Covid-19 infection had lower blood levels of vitamin D than comparable men without severe disease and, the more severe the illness, the lower the blood levels.

Before a vaccine becomes available, vitamin D can be used to stimulate immune responses to infection. Vitamin D has been widely used over many years. The basic science is well-understood and it is both effective and safe.

At the present time, taking into account existing knowledge of the potential benefits, costs, and dangers of vitamin D in the Covid-19 pandemic, the weight of the evidence is in favour of the administration of vitamin D to high risk groups at 2000-4000 IU/day during this outbreak, and ensuring adequate intakes in the whole population

It is “beyond reasonable doubt” that vitamin D supplements should be issued to all high-risk groups as a national priority.

Vitamin D3 and a global exit strategy from COVID-19

While the world is on hold as COVID-19 accelerates its global rampage, an exit strategy seems many months away. Herd immunity is a distant prospect, as are vaccines or drug treatments. However, there is a measure with the potential to help in this crisis at the cost of about 1p/day per capita, that would promote our defences, vitamin D3. This steroid hormone promotes the innate immune system, our first line of defence against microbes, including corona viruses, but the UK population is commonly D3-deficient, often severely, as is also common globally. We suggest, therefore, based on the accompanying scientific and medical evidence that efforts be made to improve vitamin D repletion to help reduce both morbidity and mortality from, and perhaps also susceptibility to, COVID-19.

We are chronically undersupplied
Vitamin D (D3) is the sunshine vitamin. Our skin makes it under summer sun but most British people don’t make enough because we live and work indoors, live at high latitude and eat little ‘wild’ oily fish (the only good food source of this vitamin), while deficiency is also a global problem.

Scientific evidence from peer reviewed publications shows that vitamin D is needed both for healthy bones and for a healthy immune system which can defend us against most bacteria and viruses at adequate blood levels of the vitamin D metabolite 25(OH)D by gene modulation, and that also reduces inappropriate inflammation.

What is an adequate blood level of 25(OH)D?
25 nmol/l was thought enough until 20 years ago, now we know it should be more than 50 nmol/l, a target used throughout the NHS. Higher levels are advised by many experts at 100 – 150 nmol/l, for optimal health (1), as are achieved by natives of the tropics.

We have a high degree of deficiency, worst in Scotland
One third to a half of all people are deficient across the UK, with severe deficiency increasingly common in the North.

Benefits of supplementation
In addition to the prevention of rickets and osteomalacia, and reduction of the risks of increasing numbers of chronic disorders, both survival with cancer and the risk of getting certain cancers are reduced by better vitamin D status (2-6).

Respiratory infection rate reduction
Evidence from animal, cell and molecular research shows that lack of vitamin D increases the risks of many chronic diseases; supplementation of deficient people can reduce many such risks, including upper respiratory tract infections as shown in a summary of 25 studies where deficient subjects amongst 11,000 participants supplemented with vitamin D showed over 70 % reduction in infection rates with certain common viruses. (7). A recent review concludes: “To reduce risk of infection, it is recommended that people at risk of influenza and/or COVID-19 consider taking 10,000 IU/d of vitamin D3 for a few weeks to rapidly raise 25(OH)D concentrations, followed by 5000 IU/d. The goal should be to raise 25(OH)D concentrations above 40–60 ng/ml (100–150 nmol/l).” (8) Those authors called for randomised trials of vitamin D in COVID-19 patients. Meanwhile, the evidence justifies ensuring that COVID-19 patients are not deficient, measuring serum 25(OH)D where possible, but more importantly, ensuring adequate supplemental intakes for all such patients. (9).

Barbara Boucher, honorary professor, London
Peter Cobbold, emeritus professor, cell biology, Liverpool
David Grimes, retired consultant physician, Manchester
Helga Rhein, retired general practitioner, Edinburgh


On 24/4/20 a letter was published in the BMJ, signed by 30 experts, pointing to evidence behind the observation of a link of low vitamin D levels to death rates in Covid-19.

7/5/20 additional evidence now available, all show worst outcomes and deaths in those with insufficient D-levels
“Normal” or “Sufficient” vitamin D level is defined as above 75 nmol/l (30 ng/ml) – 212 hospitalised patients in the Philippines: nearly 20 times better chance of a mild clinical outcome vs critical outcome – 780 patients in Indonesia, 380 died – but ONLY 16 died who had normal Vitamin D status. Insufficient Vitamin D in half of of the trial group as a whole BUT 96% of those dying. – 186 hospitalised patients in Belgium had lower blood D-levels than controls. Authors recommend D-supplements – 20 patients in US in ICU – 84% of the critical patients had insufficient vitamin D levels – 20 European countries were compared, those with lowest vitamin D levels had highest mortality, particularly older age groups in Italy, Spain and Switzerland – 176 hospitalised patients in India, severe in 92% of insufficient, but only in 61% of those with sufficient blood levels