"This study was not designed to evaluate the effect of acute changes in vitamin D status (ie, from supplementation) on prevention or treatment of COVID-19. One

"This study was not designed to evaluate the effect of acute changes in vitamin D status (ie, from supplementation) on prevention or treatment of COVID-19. One randomised trial and one quasi-experimental trial have provided evidence for a positive effect of vitamin D supplementation around time of diagnosis on COVID-19 prognosis in infected individuals. The doses of vitamin D administered in these studies could result in an acute change in the availability of vitamin D, which may support the immune system’s response to the virus, mitigate acute lung injury and contribute to improved prognosis. Our results, which pertain to long-term vitamin D status, do not preclude the possibility that therapeutic doses of vitamin D may be effective in preventing or treating COVID-19 infection. Larger randomised trials using diverse sample populations are needed to investigate the potential use of therapeutic doses of vitamin D supplementation for COVID-19 prevention and treatment."