The researchers have been examining the relationship between the likelihood of being infected and vitamin D levels for months, with this study following an earlier one that found that a vitamin D deficiency (less than 20 ng/ml) may actually raise the risk of testing positive for COVID-19.
The connection between vitamin D and COVID-19 is turning out to be a hot target for scientists.
A group of researchers and doctors have formed an international alliance aiming to encourage governments to increase recommendations for vitamin D intake to 4,000 IU daily as they believe this would reduce COVID-19 hospitalisations.
Read this excellent article which discusses Vitamin D and how it boosts the immune system to reduce the change of hospitalization when positive for COVID-19.