eng Science and Education Publishing American Journal of Biomedical Research 2328-3955 2021-11-04 9 2 36 42 10.12691/ajbr-9-2-3 AJBR2021923 article Abdulhalem A. Jan 1 Ahmed M. Aljeraisi 2 Abdullah M. Algarni 3 Mohammed A. Almozini 4 Nashwa A. Alsyed 5 Suliman A. Alharbi 6 Muhammad A. Tobaiqi 7 Hemaed Aljabri 8 Nasser M. Mulla 8 8 Alaa A. Alsayed 9 Salah Mohamed El Sayed salahfazara@yahoo.com, drsalahpediatr@yahoo.com 10 11 Laboratory and Blood Bank Director, King Fahad Hospital, Al-Madinah, Saudi Arabia Rehabilitation Hospital, Al-Madinah, Saudi Arabia Infection Control, King Fahad Hospital, Al-Madinah, Saudi Arabia Laboratory, King Fahad Hospital, Al-Madinah, Saudi Arabia Quality control, King Fahad Hospital, Al-Madinah, Saudi Arabia Immunology department, King Fahad Hospital, Al-Madinah, Saudi Arabia Department of Medicine, Taibah University, Al-Madinah, Saudi Arabia Blood Bank Department, King Fahad Hospital, Madinah Chief Risk Officer, Madinah Health Cluster, Al-Madinah, Saudi Arabia 0Department of Clinical Biochemistry and Molecular Medicine, Taibah Faculty of Medicine, Taibah University, Al-Madinah Al-Munawwarah, Saudi Arabia Controversial factors affecting COVID-19 infection include age, ethnicity, blood groups and Rh factor were investigated here. This study enrolled 2012 participants: COVID-19 cases (1006 patients), and control group (1006 subjects), 50.9% were Saudis and 49.1% were non-Saudis. Mean age for all participants was 36.0±12.7 years and ranged from 8 to 80 years. Mean age was 38.6+15.3 years for COVID-19+ve cases and 33.4±8.6 years for controls. Mean age significantly differed in COVID-19+ve cases from controls (p<0.001). COVID-19 infection was significant in Saudi participants compared to non-Saudi participants (p<0.001). In COVID-19 group, the frequencies of blood groups O, A, B and AB were 44.5%, 31.3%, 19.7% and 4.5%, respectively. The percentage of COVID-19 infection was higher in subjects having blood groups O and A. Regarding Rh factor, 94.0% of all participants were Rh+ve and 6.0% were Rh-ve. Among COVID+ve cases, 93.4% were Rh positive cases and 6.6% were Rh negative cases, while in the controls, 94.5% were Rh+ve and 5.5% were Rh-ve. The number of COVID-19+ve cases exceeded the number of healthy controls in A+ve subjects but not in O+ve and B+ve subjects. In multivariate analysis, people with blood groups B and AB were less likely to be infected (p =0.049) compared to those with groups O and A. In conclusion, older adults had greater risk of COVID-19 infection. Gatherings culture increased COVID-19 infection. Individuals with blood groups B and AB are less likely to get COVID-19 infection than O and A subjects. Rh+ve in O+ve and A+ve is associated with increased COVID-19 infection. http://pubs.sciepub.com/ajbr/9/2/3/ajbr-9-2-3.pdf COVID-19 Rh+ve Rh-ve ABO blood groups ethnicity COVID-19 infection