Two recent studies, one from the UK and one from the USA have found an association between Vitamin D deficiency and the increased health risks associated with the COVID-19 virus.

In previous studies Vitamin D has been shown to be important for the healthy functioning of the immune system and its ability to lower the risk of viral and respiratory tract infections.

In the USA those individuals who had low Vitamin D levels had an increased likelihood of becoming infected with coronavirus.

In the US just researchers looked at patients whose Vitamin D levels had been tested within a year before undergoing testing for COVID-19.  Out of just under 500 patients, those who had a Vitamin D deficiency which had not been treated, were twice as likely to be tested positive for the virus than those whose levels were sufficient.

One of the authors, David O Meltzer said: “Understanding whether treating Vitamin D deficiency changes COVID-19 risk could be of great importance locally, nationally and globally.  Vitamin D is inexpensive, generally very safe to take, and can be widely scaled.”

He and his team emphasised the importance of experimental studies to determine whether vitamin D supplementation can reduce the risk, and potentially severity, of COVID-19. They also highlighted the need for studies examining what strategies for vitamin D supplementation may be most appropriate in specific populations.

Currently 1 in 5 of the UK population are considered to have low levels of Vitamin D (defined as serum levels below 25 nmol/L).  In the US half of Americans are considered deficient with African American, Hispanic and individuals living in areas where Vitamin D exposure is difficult to achieve in winter, presenting with lower levels.

In the UK, sunlight doesn’t contain enough UVB radiation in winter (October to early March) for our skin to be able to make vitamin D. During these months, individuals need to get vitamin D from food sources and supplementation.

The UK Government advises that everyone needs vitamin D equivalent to an average daily intake of 10 micrograms (400 international units). Unfortunately  Vitamin D is not especially prevalent in our diets although sources include full fat dairy, oily fish, eggs and mushrooms.  They advise that all people should consider taking a daily supplement containing these amounts during autumn and winter months.

In the UK, a study carried out by University Hospitals Birmingham NHS Foundation Trust analysed the blood samples of 392 healthcare workers in May 2020, towards the end of the first surge of the pandemic.  over half (55%) had SARS-Cov-2 antibodies, showing that they had been infected with the virus. Those who were found to be deficient in Vitamin D reported more body aches and pains, but not respiratory symptoms including breathlessness or a continuous cough.  Vitamin D levels were also lower in staff who reported symptoms of fever.

Author Professor David Thickett, from the University of Birmingham’s Institute of Inflammation and Ageing said: “Our study has shown that there is an increased risk of COVID-19 infection in healthcare workers who are deficient in vitamin D. Our data adds to the emerging evidence from studies in the UK and globally that individuals with severe COVID-19 are more vitamin D deficient than those with mild disease. Finally, our results, combined with existing evidence further demonstrates the potential benefits of vitamin D supplementation in individuals at risk of vitamin D deficiency or who are shown to be deficient as a way to potentially alleviate the impact of COVID-19.”

Update: 14 November 2020

In a statement, a spokesperson for Nice, which sets NHS clinical guidelines, told the Guardian: “Nice and PHE received a formal request to produce recommendations on vitamin D for prevention and treatment of Covid from the secretary of state for health and social care, Matt Hancock, on October 29.”


David O. Meltzer, Thomas J. Best, Hui Zhang, Tamara Vokes, Vineet Arora, Julian Solway. Association of Vitamin D Status and Other Clinical Characteristics With COVID-19 Test Results. JAMA Network Open, 2020; 3 (9): e2019722 DOI: 10.1001/jamanetworkopen.2020.19722

‘Vitamin D status and seroconversion for COVID-19 in UK healthcare workers who isolated for COVID-19 like symptoms during the 2020 pandemic’