medRxiv preprint doi: https://doi.org/10.1101/2020.08.02.20166785; this version posted August 4, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license . The Lebanese Cohort for COVID-19; A Challenge for the ABO Blood Group System Athar Khalil. PhDa,c, Rita Feghali. MDb*, Mahmoud Hassoun. MDc* a,c Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon bDepartment of Laboratory Medicine, Rafik Hariri University Hospital, Beirut, Lebanon cDepartment of Pulmonary and Intensive Care Unit, Rafik Hariri University Hospital, Beirut, Lebanon *Corresponding authors Abstract A sudden outbreak of pneumonia caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has rapidly spread all over the world facilitating the declaration of the resultant disease as a pandemic in March,2020. In Lebanon, the fast action of announcing a state of emergency with strict measures was among the factors that helped in achieving a successful containment of the disease in the country. Predisposing factors for acquiring COVID-19 and for developing a severe form of this disease were postulated to be related to epidemiological and clinical characteristics as well as the genomics signature of a given population or its environment. Biological markers such as the ABO blood group system was amongst those factors that were proposed to be linked to the variability in the disease course and/or the prevalence of this infection among different groups. We therefore conducted the first retrospective case-control study in the Middle-East and North Africa that tackles the association between the blood group types and the susceptibility as well as the severity of SARS-CoV2 infection. Opposing to the current acknowledged hypothesis, our results have challenged the association significance of this system with COVID-19. Herein, we highlighted the importance of studying larger cohorts using more rigorous approaches to diminish the potential confounding effect of some underlying comorbidities and genetic variants that are known to be associated with the ABO blood group system. Word count: 227 Keywords: SARS-CoV-2, COVID-19 cohort, ABO blood group system, Infection predisposition. 1 NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice. medRxiv preprint doi: https://doi.org/10.1101/2020.08.02.20166785; this version posted August 4, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license . 1- Introduction In December 2019, a sudden outbreak of pneumonia has emerged in Wu Han City, China that then spread all over the world1. This coronavirus disease 2019 (COVID-19) as named by the World Health Organization(WHO), is caused by the Betacoronavirus SARS-CoV-2 that targets primarily the human’s lower respiratory tract. COVID-19 is mainly characterized by dry cough, dyspnea, fever, and bilateral lung infiltrates upon imaging. The primary cause of death among the infected patients remains to be the acquired severe respiratory failure 2. The fast spread of this contagious disease reaching around 200 countries in a short period of time has facilitated the declaration of COVID-19 outbreak as a pandemic on March 11th 20203. Till this date, the global number of confirmed positive cases exceeded the 10 million and caused more than 500,000 deaths4. In Lebanon, the official authorities had forced strict measures shortly after detecting the first case of COVID-19. This fast action of declaring a state of emergency in the country was among the factors that helped in the successful containment of the disease. So far, the Ministry of Public Health has confirmed 1885 cases of COVID-19 and 36 associated deaths 5,6. As such, Lebanon has avoided the best-case projection scenario, according to China modeling, that anticipated tens of thousands cases to be diagnosed in our region. Comparing to other countries with small population like Norway which reported till this date around 8,936 confirmed cases with 251 deaths from a total population of 5.3 million, Lebanon did a good job in managing the spread of this disease 4,7. Yet, it should be noted that the predisposition for acquiring COVID-19 and for developing severe form of this disease is also known to be affected by some epidemiological and clinical characteristics of the population. The main studied risk factors are age, sex, and some chronic conditions such as diabetes and cardiovascular diseases8,9. On the contrary, the establishment of biological markers for predicting the variability in the disease course or the prevalence of infection among different groups is not yet elucidated10. From that perspective and due to the highly tackled association between blood groups and the susceptibility/severity of various diseases such as SARS-CoV-1, P. falciparum, H. pylori, Norwalk virus, hepatitis B virus, and N. gonorrhoeae, investigations on its association with COVID-19 cases was evaluated11. Zhao et.al were the first to report an association between ABO blood group and the susceptibility to SARS-CoV-212. Afterwards, several studies has emerged to pinpoint again on the increased risk for SARS-CoV-2 infection and the higher mortality rate among blood group A individuals as compared to that of blood group O10–13. The explanation of this linkage was attributed to several hypothesis such as the presence of an extra sugar N-acetyl galactosamine on the surface of blood group A cells that can possibly propose a more pathogen-host contact or the presence of anti-A antibodies IgGs in the serum of O blood type carriers that can inhibit the virus–cell adhesion process (Figure-1)13,14. Recently, a newly published article in The New England Journal of Medicine presented a genetic piece of evidence that established a potential role of the ABO blood-group system as a risk factor for acquiring COVID-19. In their article, Ellinghaus et. al have identified the rs657152 variant that coincided on the ABO blood group locus (9q34.2) to be associated with COVID-19–induced respiratory failure15. 2 medRxiv preprint doi: https://doi.org/10.1101/2020.08.02.20166785; this version posted August 4, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license . Although all the above mentioned articles provided a consistent association between the ABO blood system and COVID-19 disease, yet, all of these studies emphasized on the importance of investigating this association in larger clinical datasets among different populations. For this reason, we decided to evaluate the association between different blood types and the susceptibility as well as severity of SARS- CoV2 infection in the Lebanese Cohort. 2- Methods a- Data Source Medical records for COVID-19 patients and their clinical characteristics were obtained from the electronic medical database at Rafik Hariri University Hospital (RHUH). The retrieved variables for COVID-19 patients were age, sex, blood group and severity of their disease. For control population, only blood group types ware retrieved. b- Study design This is a retrospective case-control study with 146 COVID-19 patients and 6497 participants in the control group. The case group consisted of individuals with known blood types who were diagnosed with COVID-19 and hospitalized in RHUH between February, 2020 and June, 2020. The diagnosis of COVID-19 was confirmed by a positive real-time reverse transcriptase polymerase-chain-reaction test for SARS-CoV-2 on nasal and pharyngeal swab specimens from patients. For the control group, blood groups data for all individuals who were hospitalized in RHUH between 01/01/2018 till 24/06/2020 were included. For the control group, all blood samples were typed by forward test tube method while for the case group the typing was done by both forward and reverse testing. Severity classification criteria was adopted from the interim guidelines of the World Health Organization and the National Health Commission of China. Based on the patients' symptoms, laboratory results and imaging findings at admission, the disease severity of COVID-19 patients was categorized into four types: mild, moderate, severe, and critical16,17. Given the small sample size of our cohort and the low number of severe and critical cases, we combined these two categories together. Briefly,1) Mild cases patients were those diagnosed with upper respiratory symptoms but with no imaging abnormalities 2) Moderate patients were diagnosed based on the presence of at least two of the following : dyspnea, cough, and body temperature > 38oC, with imaging abnormalities, 3) Severe cases were characterized by respiratory distress with respiratory rate ≥ 30 Breaths Per Minute (BPM), O2 Saturation ≤ 93%, and PaO2/FiO2 ≤ 300 mmHg while those categorized as 4) critical cases are those who had acute respiratory failure necessitating non-invasive or/and invasive ventilation with the presence of multi organ failure such as renal failure, liver failure and heart failure, shock and imaging with more than 50 % progression within 24-48 hours16. This study was approved by the Ethical Committee of RHUH. Due to the retrospective nature of the study and because no identifying information relating to participants was included, written informed consent was waived. All experimental protocols were conducted according to the Strengthening of the Reporting of Observational Studies in Epidemiology guidelines.