Is the oral cavity a reservoir for prolonged SARS-CoV-2 shedding?

Limited knowledge about the contagiosity and case fatality rate of COVID-19 as well as the still enigmatic route of transmission have led to strict limitations of non-emergency health care especially in head and neck medicine and dentistry. There are theories that the oral cavity provides a favorable environment for SARS-CoV-2 entry and persistence which may be a risk for prolonged virus shedding. However, intraoral innate immune mechanisms provide antiviral effects against a myriad of pathogenic viruses. Initial hints of their efficacy against SARS-CoV-2 are surfacing. It is hypothesized that intraoral immune system activity modulates the invasion pattern of SARS-CoV-2 into oral cells. Thus, the significance of intraoral tissues for SARS-CoV-2 transmission and persistence cannot be assessed. The underlying concept for this hypothesis was developed by the critical observation of a clinically asymptomatic COVID-19 patient. Despite a positive throat swab for SARS-CoV-2, molecular pathologic analysis of an oral perisulcular tissue specimen failed to detect SARS-CoV-2 RNA. More research effort is necessary to define the true origin of the contagiosity of asymptomatic COVID-19 patients.