Scientists at the University of Edinburgh have found that sun rays could help to boost immunity against Covid-19, thanks to a study of mortality rates in the US last year.

The study found that sunnier parts of the US have proportionally seen fewer deaths from the virus, with the results replicated in both the UK and Italy.

Researchers from the University of Edinburgh compared all recorded deaths from Covid-19 in the US from January to April 2020 with UV levels for the same time period. They found that people living in areas with the highest level of UVA rays had a lower risk of dying compared with areas experiencing lower levels.

The study was led by Dr Richard Weller and Professor Chris Dibben at the University, with the results appearing in the British Journal of Dermatology.

Dr Weller, Consultant dermatologist and Reader at the University of Edinburgh, said:

There is still so much we don’t understand about Covid-19, which has resulted in so many deaths worldwide. These early results open up sunlight exposure as one way of potentially reducing the risk of death.

If we can work out how sunlight reduce Covid deaths that could suggest new treatments.

The benefits of Vitamin D in fighting Covid, which can be produced through exposure to UVB sun rays, has already been well documented since the start of the pandemic.  However, the team at the University of Edinburgh claim that this particular reduction in risk could not be explained by higher levels of Vitamin D, since they carried out the study in areas with insufficient levels of UVB sun rays – or during those areas’ Vitamin D winter.

The scientists behind the study believe that one reason for the lower number of deaths could be that sunlight causes the skin to release nitric oxide, which has been proven to inhibit the virus from replicating. They also point to research proving that sunlight exposure can reduce the risk of heart problems, which is a known risk factor for those who catch Covid-19.