RESUMEN
Abstract: Vitamin D is a hormone which plays a vital role in immune response regulation, including the prevention of inflammation and autoimmunity. Insufficient vitamin D may increase the risk of infection. Vitamin D deficiency is not the only factor linked to an elevated risk of COVID-19 infection. Recent studies have discovered a link between SARS-COV-2 infection risk and blood type. This study was aimed to examine the association of vitamin D and blood groups with the severity of COVID-19. A retrospective study was conducted on 224 confirmed COVID-19 patients, aged between 18 and 89 years old. Patients were divided into three groups (asymptomatic, moderate, and severe cases), and serum 25(OH)D concentration and blood group were analyzed for all the patients. Data of the severe cases were obtained from Souq Althalath Isolation Center, Tripoli, Libya, while moderate and asymptomatic cases were obtained from Abushusha Polyclinic and Aldahmani COVID Filtration Center, during 22nd February 2021 and 28th April 2021 and serum 25(OH)D concentration and blood group were statistically analyzed for all the patients. The percentages of males andfemales were found to be 47.3% and 52.7%, respectively. Disease severity was distributed as follows: 12.5% asymptomatic, 44.6 % moderate and 42.9% severe. Most of the severe cases had vitamin D deficiency (88.5%). Among the severely ill patients, 39.6% had blood group A and 09.4% had group O, while 22.9%, and 28.1% had blood group B and AB, respectively. In contrast, among the asymptomatic patients, only 7.1% had group A and 85.7% had group O. Overall, the difference in the distribution pattern of blood group in the three severity categories was highly significant (p < 0.001). The prevalence of Rh positivity among asymptomatic, moderate and severe cases was 78.6%, 76.0%, and 60.4%, respectively. This study concludes that insufficient vitamin D levels might influence the severity of COVID-19. COVID-19 patients with blood group A and those who are Rh-positive could be more vulnerable to developing COVID-19 severity