Clinical trial to investigate whether vitamin D protects against COVID-19

13 October 2020

CORONAVIT will run for six months and involve more than 5,000 people to find out whether a ‘test-and-treat’ approach to correct people’s vitamin D deficiency during winter will reduce the risk and/or severity of COVID-19 and other acute respiratory infections.

People will take part in the study from their homes, without any face-to-face visits needed, as all vitamin D tests and supplements will be sent via the post. Any UK resident aged 16 or more can participate if they are not already taking high-dose vitamin D. To register interest, people can contact the study team on coronavit@qmul.ac.uk.

Strategies to boost the UK population’s immunity to respiratory infections are urgently needed pending development of an effective vaccine for coronavirus. There have been recent debates as to whether vitamin D – the ‘sunshine vitamin’ – could play a key role in protecting people from COVID-19; however, definite evidence on this is lacking.

Lead researcher Professor Adrian Martineau from the Institute of Population Health Sciences at Queen Mary University of London said: “There is mounting evidence that vitamin D might reduce the risk of respiratory infections, with some recent studies suggesting that people with lower vitamin D levels may be more susceptible to coronavirus.

“Many people in the UK have low vitamin D levels, particularly in the winter and spring, when respiratory infections are most common. Vitamin D deficiency is more common in older people, in people who are overweight, and in Black and Asian people – all of the groups who are at increased risk of becoming very ill with COVID-19.

“The UK government already recommends that people take a low-dose vitamin D supplement over the winter to protect their bone health, but we do not know if this will have effect on COVID-19 or if higher doses might be able to provide protection against the virus. The CORONAVIT trial will test whether higher doses of vitamin D might offer protection against winter respiratory infections including COVID-19.”

UK sunshine is too weak to make vitamin D in the skin between October and April, and dietary sources of vitamin D are limited: consequently, around 2 in 5 of the UK adult population have inadequate levels of vitamin D over winter and spring. The UK government recommends that the general population considers taking vitamin D supplements at a dose of 400 International Units (IU) or 10 micrograms per day during winter and spring. This has recently been extended to a recommendation of year-round supplementation in view of potentially decreased sun exposure during ‘lockdown’.

However, early unpublished data from the Queen Mary team shows that 2 in 3 people are not following this advice, potentially due to a reluctance to buy and take a supplement without a test result that shows they are vitamin D deficient.

The intervention to be evaluated involves doing a postal finger prick vitamin D test, which will be processed in an NHS lab. Participants who are found to have low levels of vitamin D in their blood will then be given a six months’ supply of either 800 or 3,200 IU of vitamin D a day.

The research team will then track the incidence of doctor-diagnosed or laboratory-confirmed acute respiratory infection in the participants, including COVID-19, to see whether vitamin D supplementation has had an effect on their risk and severity of infection.

Principal Investigator of the study, Dr David Jolliffe from the Blizard Institute and Institute of Population Health Sciences at Queen Mary University of London, added: “CORONAVIT trial has the potential to give a definitive answer to the question of whether vitamin D offers protection against COVID-19. Vitamin D supplements are low in cost, low in risk and widely accessible; if proven effective, they could significantly aid in our global fight against the virus.”