Nasal microbiota could point to who develops COVID-19 symptoms

The microbiota in the nose and upper throat likely contains biomarkers for assessing how sick an individual infected with SARS-CoV-2, the virus that causes the novel coronavirus (COVID-19), may get and for developing new treatment strategies to improve their outcome, according to new research published in the journal Diagnostics.

This nasopharyngeal microbiota is generally considered a frontline protection against viruses, bacteria and other pathogens that enter these natural passageways, the researchers said.

For the study, researchers examined the microbiota of 27 individuals ages 49 to 78 years old who were negative for the virus, 30 who were positive but had no symptoms, and 27 who were positive with moderate symptoms that did not require hospitalization.

The most significant changes were in those who were symptomatic, including about half those patients not having enough microbiota to sequence, the researchers said. Additionally, the researchers said they were surprised to find these “low reads” of bacteria in the nasopharyngeal cavity of symptomatic individuals versus only two and four individuals in the negative and positive with no symptoms groups, respectively. Most of the positive individuals with no symptoms still had sufficient microbiota, they said.

Based on experience with microbiota in the gastrointestinal tract, the researchers said the different microbiota content and size is another good bet and they both would like a definitive answer. The researchers found differences in the type of bacteria as well, although they said that the function of some of the bacteria they found are not well understood.

The researchers decided to look at the microbiota in the upper part of the respiratory system called the nasopharynx of older individuals. The mucus-producing lining of this area works like a natural barrier to invaders and there also is a significant complement of immune cells present, and their response to respiratory viruses is key, the researchers said. The area also is abundant with ACE-2 receptors, to which the spiky virus binds, so it is a major landing spot for this virus, researchers said.

The findings indicate that the altered microbiota in the symptomatic patients impacted their immune response to the virus.

Editor's note: Click here for more information and ongoing COVID-19 updates for integrative healthcare professionals.