Why Do People With Diabetes Have a High Risk for Severe COVID-19 Disease?-A Dental Hypothesis and Possible Prevention Strategy.

The SARS-CoV-2 virus causes symptoms in infected individuals ranging from mild flu symptoms via severe COVID-19 pneumonia requiring ventilation to death. Risk factors for severe courses are age, diabetes, hypertension and other serious diseases. The main entry portal for the virus into the body is probably the oral mucosa, as it is a known location of virus accumulation. The suspected main receptor is highly expressed in this tissue. Such a route of penetration of the virus into the body provides plausible explanations for severe COVID-19 courses seen particularly in older diabetes patients. The immune system of people with diabetes is considered to be generally impaired. Diabetes induces a chronic systemic inflammation, which regularly manifests as periodontitis. Furthermore, frequent hyperglycaemia is known to lead to additional weakening of the oral mucosa barrier. It is therefore recommended that preventive measures in diabetes patients should also include the bucchal area. Knowledge of the inflammatory status in the mouth and throat may be helpful for identification of patients at particular risk. An established biomarker for measuring the degree of orall inflammation is activated matrix metalloproteinase 8 (aMMP8), for which saliva tests are available. From our point of view, the current recommendations for the prevention of SARS-CoV-2 associated COVID-19 disease should therefore be extended to include the aspects of measurement and sanitation of mouth and throat and regular disinfection of this area.