Nose bacteria may occupy the key to your COVID-19 vulnerability

According to groundbreaking research, your risk of COVID-19 may depend on which bacteria call your nose home, which provides new insights about some people being more susceptible to viral infections than others.

Scientists at George Washington University have found that certain bacteria living in the nose affect the levels of key proteins needed by SARS-COV-2 to enter human cells, which could explain one of the most enduring mysteries of the pandemic – why infection rates change so dramatically among people with similar exposure risks.

“We already know that the virus SARS-COV-2 enters the body through the respiratory tract, and the nose is a key entry point. The bacteria in the nose can affect the protein levels of the virus infects cells, which is a key entry point.

The study, published April 9 in the journal ebiomedicine, analyzed nasal swab samples from more than 450 people, including some who later tested positive for Covid-19. The researchers focused on two proteins ACE2 and TMPRSS2, which are the doorways for the virus to enter the nose cells.

People with high protein expression are three times more likely to test positive for -19, while those with moderate levels are twice as likely to be at risk. Even more disturbingly, the study found that expression levels usually peaked a few days before individuals tested positive, potential signals increasing vulnerability to infection.

When the researchers looked at what affected these protein levels, they turned to the nasal microbiome—a community of bacteria that the nose naturally inhabited. They identified three bacterial villains and a potential hero.

“Some bacteria in the nose may be setting the stage for viruses like SARS-COV-2, or even opening the door,” explains Daniel Park, a senior research scientist at GW.

In particular, three bacteria – Staphylococcus aureus, Haemophilus influenzae and Catalaria/non-liquefaciens – were associated with higher expression of viral inlet proteins and increased the risk of COVID-19. Studies show that about 20% of participants carry enough Staphylococcus aureus, almost double the risk of elevated levels of these key proteins.

However, another common rhinoplasty bacteria, dolosigranulum pigrum, is associated with lower levels of inlet protein and may provide some protection against the virus.

The study also reveals interesting gender-based differences. Women usually have higher levels of these viruses entering proteins, which is consistent with previous studies that show that women have a higher rate of Covid-19 infection. However, men with elevated levels face greater risk of infection, suggesting that these proteins may cause greater vulnerability to males.

These findings open up interesting possibilities for prevention of common prevention. Monitoring these protein levels may identify high-risk individuals before infection. More importantly, modifying the nasal microbiome may become a novel prevention strategy.

“We’re just starting to understand the complex relationship between the nasal microbiome and our health,” Liu said. “This study shows that the bacteria in our noses and how they interact with cells and immune systems in the nasal cavity – can play an important role in determining auxiliary infections such as our risk of suffering from respiratory infections.”

The team is now exploring interventions targeting the nasal microbiome, such as specialized nasal sprays or real-time biotherapeutics, that can reduce the risk of infection—it is possible to create new tools to prevent respiratory viral infections in future pandemics.

As variants continue to emerge and transition to a common 19-year-old transition to an epidemic, it becomes increasingly important to understand these biohazard factors. The study shows that while masks, vaccines and social distancing remain vital protection measures, the micro-ecosystems within our noses may be another key battlefield in our ongoing battle against the coronavirus.