Study Reveals COVID-19 Pathway From the Oral Cavity to Lungs

Compared to other risk factors, periodontal disease and poor oral hygiene may be more accurate predictors of the severity of COVID-19 symptoms a patient experiences, a new study has found. Research from an international team from the United States, United Kingdom and South Africa indicates the oral cavity and nose are central entry points for the virus. Published in the Journal of Oral Medicine and Dental Research, the paper, “The COVID-19 Pathway: A Proposed Oral-Vascular-Pulmonary Route of SARS-CoV-2 Infection and the Importance of Oral Healthcare Measures,” suggests effective oral hygiene can reduce the risk of transmission from the patient’s oral cavity to the lungs.

The authors note that high concentrations of SARS-CoV-2 in saliva, along with periodontal disease, are associated with an increased risk of death from COVID-19. Consequently, the team explored the oral cavity-COVID-19 connection, outlining the route taken by the virus as it moves through saliva, via gingival capillaries, into the blood vessels of the neck and chest, through the heart, and to blood vessels in the lungs.

Pointing to evidence that indicates blood vessels of the lungs, rather than airways, are initially affected in COVID-19 disease, the researchers conclude the virus reaches the lungs through blood vessels since the airways do not appear inflamed in computed tomography scans, while the blood vessels appear abnormal.

Given the oral cavity connection, the team proposes that oral biofilm accumulation and periodontal inflammation increase the likelihood of SARS-CoV-2 reaching the lungs, possibly resulting in more severe infections. As such, the authors say efforts to improve oral health — including toothbrushing, interdental cleaning and mouthrinse use — may help mitigate COVID-19 infection and severity.

From Decisions in Dentistry. June 2021;7(6),10.