SARS, MERS, COVID-19: Identification of Patients at a Higher Risk: A Narrative Review

The different presentations, comorbidities, and outcomes of COVID-19 highlight the importance of early identification and proper triage of patients. High-risk patients can be divided into patients with common comorbidities and patients with special categories. Common comorbidities include, but are not limited to, Cardiovascular Disease (CVD), Diabetes Mellitus (DM), immunosuppression, underlying respiratory disease, and obesity. Certain categories of COVID-19 patients are also at increased risk, including neonates and pregnant women.  In the present article, we delineate the reported risk factors for acquisition of infection, and for increased severity of the clinical disease. We also comparatively analyze those risk factors associated with COVID-19 and with the antecedent human acute respiratory syndrome-causing viruses, SARS-CoV-1 and MERS-CoV. We hypothesize that the structural similarities of the three viruses predict a similarity in the profile of high-risk patients. Several pathophysiological patterns have been detected to support this theory.