How COVID-19 Complications Can Start in the Mouth

Although COVID-19 affects the respiratory system, it may not actually reach the lungs through inhalation as previously thought. In fact, a new hypothesis believes that the virus may actually enter the bloodstream in the mouth, where it will then travel to the lungs. At this time, this idea is nothing more than a hypothesis, however it does make some interesting points. This new hypothesis was recently published in the Journal of Oral Medicine and Dental Research and is titled, The COVID-19 Pathway: A Proposed Oral-Vascular-Pulmonary Route of SARS-CoV-2 Infection and the Importance of Oral Healthcare Measures.

While the actual article explains the hypothesis in great detail and with supportive research and references, a brief overview will be provided in this blog. The main goal of this is to explain the basis of this hypothesis and how it relates to oral health. For starters, the article notes that the SARS-CoV-2 virus is able to infect both the saliva and gingival crevicular fluid (GCF). It is important to note that very little GCF is found in people with healthy gums, while those with gum disease have higher levels of GCF. The article postulates that more GCF could lead to a higher viral load. 

Once the virus has infected the saliva and GCF, it can accumulate in these fluids. The article notes that this becomes especially problematic when periodontal pockets are also present. Periodontal pockets are small gaps between the teeth and gums created by inflammation that causes the gums to pull away from the teeth. In addition to collecting plaque and bacteria, the article notes that the SARS-CoV-2 virus can also accumulate in these pockets. This can lead to the survival and replication of the virus. 

When large amounts of bacteria accumulate in the periodontal pockets, past dental research tells us that the bacteria can overwhelm the mouth’s immune defenses and pass into the bloodstream. Once in the bloodstream, the bacteria can travel to other parts of the body and cause various problems such as endocarditis, pregnancy complications, and respiratory infection. Just as large amounts of bacteria can enter the bloodstream in this way, the article notes that the SARS-CoV-2 virus can do the same. Once in the bloodstream, the virus will flow through the veins of the neck and chest into the heart, where it will then be pumped into the arteries that supply the lungs. Unfortunately, this means that the virus can infect the lungs. 

Once a COVID-19 infection has started, the article notes that there is a higher rate of complications in people with periodontitis. Specifically, it is mentioned that periodontitis can increase the risk of death, the need for intensive care, and the necessity of ventilation. The article believes that this is due to the fact that periodontitis allows for a higher viral load in the mouth that is then continually circulated into the lungs. While this idea is still being researched, it is recommended to practice good oral hygiene as a possible way to decrease the risk of serious COVID-19 complications.