Scan to discover online Background & Objective: Coronavirus disease 2019 (COVID-19) is the most recent emerging viral disease. Defining the epidemiological aspects and factors influencing the susceptibility of the patients to COVID-19 has been an ongoing struggle. In the present study, we have investigated the connection between ABO histo-blood group phenotypes and the COVID-19. Methods: This study was conducted on 397 patients with confirmed diagnoses of COVID-19 admitted to our center. Also, 500 individuals were selected to form the controls, all of whom had been disclosed to the same medical center in June 2019, before the onset of the outbreak. Results: Our results demonstrated ABO histo-blood phenotypes are correlated with patients' susceptibility to the infection. A higher rate of infection was observed among patients with the AB histo-blood group, while patients with the O histo-blood group have shown a lower rate of infection. The Rh blood group phenotype was not statistically significant in determining a patient's vulnerability. Conclusion: Similar to several previous studies about other viral diseases' association with ABO histo-blood groups, we have concluded that an individual's ABO histo-blood group phenotype and his/her susceptibility to COVID-19 are indeed connected. So far, only one research has been conducted about this association. Interestingly, while we observed a decreased vulnerability to the disease among patients with an O histo-blood group, we have reached discordant results regarding the increased susceptibility among individuals with an AB histo-blood group, unlike A histo-blood group in the previous study.

Background and Objectives The outbreak of COVID‐19 has created a global public health crisis. Little is known about the predisposing factors of this infection. The aim of this study was to explore an association between the serum vitamin D level, obesity, and underlying health conditions, as well as the vulnerability to COVID‐19 in the Iranian population. Methods We conducted a case–control study of 201 patients with coronavirus infection and 201 controls. Cases and controls were matched for age and gender. The study was carried out for 2 months (February 2020–April 2020) at Imam Khomeini Hospital Complex, Tehran, Iran. Serum 25(OH) vitamin D was measured using the enzyme‐linked immunosorbent assay method. Information containing age, gender, clinical symptoms, body mass index, computed tomography scan findings, and underlying health conditions related to each participant were elicited from health records. Results A significant negative correlation (p = .02) was observed between the serum vitamin D level and developing coronavirus infection. Also, the results showed that the COVID‐19 cases were more likely to be overweight than the controls (p = .023). Diabetes mellitus, hypertension, and respiratory infections were found in 20.89%, 9.65%, and 6.96% of cases, respectively. These underlying health conditions were not significantly different between cases and controls (p = .81). Conclusions Vitamin D deficiency and obesity are two main predisposing factors associated with the vulnerability to coronavirus infection in the Iranian population.