Abstract: Southern African Journal of Infectious Diseases ISSN: (Online) 2313-1810, (Print) 2312-0053 Page 1 of 6 Original Research Vitamin D status and COVID-19 severity Authors: Senrina Kalichuran1 Sarah A. van Blydenstein1,2 Michelle Venter1,3 Shahed Omar4,5 Affiliations: 1 Department of Internal Medicine, Faculty of Health Sciences, School of Clinical Medicine, University of the Witwatersrand, Johannesburg, South Africa Department of Pulmonology, Faculty of Internal Medicine, Chris Hani Baragwanath Academic Hospital, Johannesburg, South Africa 2 Department of Infectious Diseases, Chris Hani Baragwanath Academic Hospital, Johannesburg, South Africa 3 Department of Critical Care, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa 4 Department of Critical Care, Chris Hani Baragwanath Academic Hospital, Johannesburg, South Africa 5 Corresponding author: Senrina Kalichuran, senrina.kalichuran@gmail. com Dates: Received: 25 Oct. 2021 Accepted: 04 Mar. 2022 Published: 26 Apr. 2022 How to cite this article: Kalichuran S, van Blydenstein SA, Venter M, Omar S. Vitamin D status and COVID-19 severity. S Afr J Infect Dis. 2022;37(1), a359. https://doi.org/10.4102/ sajid.v37i1.359 Read online: Scan this QR code with your smart phone or mobile device to read online. Background: Age, body mass index (BMI) and pre-existing comorbidities are known risk factors of severe coronavirus disease 2019 (COVID-19). In this study we explore the relationship between vitamin D status and COVID-19 severity. Methods: We conducted a prospective, cross-sectional descriptive study. We enrolled 100 COVID-19 positive patients admitted to a tertiary level hospital in Johannesburg, South Africa. Fifty had symptomatic disease (COVID-19 pneumonia) and 50 who were asymptomatic (incidental diagnosis). Following written informed consent, patients were interviewed regarding age, gender and sunlight exposure during the past week, disease severity, BMI, calcium, albumin, magnesium and alkaline phosphatase levels. Finally, blood was collected for vitamin D measurement. Results: We found an 82% prevalence rate of vitamin D deficiency or insufficiency among COVID-19 patients. Vitamin D levels were lower in the symptomatic group (18.1 ng/mL ± 8.1 ng/mL) than the asymptomatic group (25.9 ng/mL ± 7.1 ng/mL) with a p-value of 0.000. The relative risk of symptomatic COVID-19 was 2.5-fold higher among vitamin D deficient patients than vitamin D non-deficient patients (confidence interval [CI]: 1.14–3.26). Additional predictors of symptomatic disease were older age, hypocalcaemia and hypoalbuminaemia. Using multiple regression, the only independent predictors of COVID-19 severity were age and vitamin D levels. The patients exposed to less sunlight had a 2.39-fold increased risk for symptomatic disease compared to those with more sunlight exposure (CI: 1.32–4.33). Conclusion: We found a high prevalence of vitamin D deficiency and insufficiency among patients admitted to hospital with COVID-19 and an increased risk for symptomatic disease in vitamin D deficient patients. Keywords: vitamin D; COVID-19; severity; Johannesburg; South Africa.