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

Schetelig, J.; Baldauf, H.; Wendler, S.; Heidenreich, F.; Real, R.; Kolditz, M.; Rosner, A.; Dalpke, A.; de With, K.; Lange, V.; Markert, J.; Barth, R.; Bunzel, C.; Endert, D.; Hofmann, J.; Sauter, J.; Bernas, S. N.; Schmidt, A. H.

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/m2, 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/m2. 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.