1 Centre for Immunobiology, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK. a.martineau@qmul.ac.uk.
2 Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, USA.
Vitamin D has received much interest during the COVID-19 pandemic as a potential prophylactic or therapeutic agent — but do the available data support its use?