Severity of Respiratory Infections due to SARS-CoV-2 in Working Population: Age and Body Mass Index Outweigh ABO Blood Group

Background With increasing rates of SARS-CoV-2 infections and the intention to avoid a lock-down, the risks for the working population are of great interest. No large studies have been conducted which allow risk assessment for this population. Methods DKMS is a non-profit donor center for stem cell donation and reaches out to registered volunteers between 18 and 61 years of age. To identify risk factors for severe COVID-19 courses in this population we performed a cross-sectional study. Self-reported data on oro- or nasopharyngeal swabs, risk factors, symptoms and treatment were collected with a health questionnaire and linked to existing genetic data. We fitted multivariable logistic regression models for the risk of contracting SARS-CoV-2, risk of severe respiratory infection and risk of hospitalization. Findings Of 4,440,895 contacted volunteers 924,660 (20.8%) participated in the study. Among 157,544 participants tested, 7,948 reported SARS-CoV-2 detection. Of those, 947 participants (11.9%) reported an asymptomatic course, 5,014 (63.1%) mild/moderate respiratory infections, and 1,987 (25%) severe respiratory tract infections. In total, 286 participants (3.6%) were hospitalized for respiratory tract infections. The risk of hospitalization in comparison to a 20-year old person of normal weight was 2.1-fold higher (95%-CI, 1.2-3.69, p=0.01) for a person of same age with a BMI between 35-40 kg/m[2][1], it was 5.33-fold higher (95%-CI, 2.92-9.70, p<0.001) for a 55-year old person with normal weight and 11.2-fold higher (95%-CI, 10.1-14.6, p<0.001) for a 55-year old person with a BMI between 35-40 kg/m[2][1]. Blood group A was associated with a 1.15-fold higher risk for contracting SARS-CoV-2 (95%-CI 1.08-1.22, p<0.001) than blood group O but did not impact COVID-19 severity. Interpretation In this relatively healthy population, the risk for hospitalizations due to SARS-CoV-2 infections was moderate. Age and BMI were major risk factors. These data may help to tailor risk-stratified preventive measures. Funding DKMS initiated and conducted this study. The Federal Ministry of Education and Research (BMBF) supported the study by a research grant (COVID-19 call (202), reference number 01KI20177). ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement DKMS initiated and conducted this study. The Federal Ministry of Education and Research (BMBF) supported the study by a research grant (COVID-19 call (202), reference number 01KI20177). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Institutional Review Board of the Technische Universitaet Dresden (IRB00001473) All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes The authors confirm that the data supporting the results of this study are available in the article [and/or] its supplementary materials. [1]: #ref-2