The Oral-Vascular-Pulmonary Infection Route: a Pathogenic Mechanism Linking Oral Health Status to Acute and Post-Acute COVID-19

Abstract

Abstract Purpose of Review In recent years, much attention has focused on the role of poor oral health in the development or worsening of systemic diseases, including COVID-19. The mouth is an important site of cellular infection early in the disease course of COVID-19. We review how oral pathology, and specifically viral infection within the oral cavity, may mediate the disease severity and duration of COVID-19. In particular, the previously reported model of SARS-CoV-2 vascular delivery from the mouth to the lungs via the bloodstream is revisited. Recent Findings We previously proposed that an oral-vascular-pulmonary route of infection could facilitate severe lung disease in COVID-19. This pathway could also explain the vital link between periodontitis and COVID-19 severity, including higher mortality risk. This model of pathogenesis is reconsidered in light of recent findings regarding the involvement of the mouth as a viral reservoir, and pathological processes in the blood, pulmonary vasculature, and elsewhere in the body. Oral dysbiosis in COVID-19 and the effect of oral hygiene in mitigating disease severity are discussed. The evidence for viral persistence in the mouth and intravascular viral passage from the mouth to the rest of the body via blood is also discussed in the context of post-acute COVID (long COVID). Summary High viral load in the mouth and poor oral health status are associated with COVID-19 disease severity, increasing the risk of death. Pathophysiological links between viral activity in the mouth, oral health status, and disease outcome in the lungs and blood provide a rationale for further evaluation of the oral-vascular-systemic pathway in patients with acute COVID-19 and long COVID. The potential benefits of oral hygiene protocols and periodontal procedures in COVID-19 also warrant further investigation.