Nasal swab test can predict severe COVID-19 infections

COVID-19 presents a broad range of symptoms, varying in intensity from mild to severe and even life-threatening, especially among those with pre-existing health conditions. Despite current strains generally producing milder symptoms, individuals with underlying conditions still face heightened risks of severe illness. 

Now, researchers at Emory University have made a breakthrough in predicting COVID-19 severity by analyzing autoantibodies in the nasal cavity. 

The findings, published in the journal Science Translational Medicine, offer a path to more tailored treatment plans that could benefit high-risk individuals by informing rapid treatment options, such as taking antiviral medications like Paxlovid within a week of symptom onset to reduce the risk of severe complications.

Tracking COVID-19 through antibodies

The study monitored 125 patients with COVID-19 ranging from mild to severe cases over nearly two years. The researchers tracked antibodies both in the blood and in the nasal airways and found that over 70% of individuals with mild or moderate COVID-19 developed specific autoantibodies in the nasal cavity. 

Surprisingly, these nasal autoantibodies were associated with milder symptoms, better antiviral responses, and quicker recovery times.

According to the study’s lead researcher, Eliver Ghosn, a faculty member at Emory’s Lowance Center for Human Immunology and Emory Vaccine Center, the presence of these autoantibodies in the nose appears to play a protective role by regulating the immune system. 

“Generally, autoantibodies are associated with pathology and a negative prognosis, causing increased inflammation that would indicate more severe disease,” Ghosn said. “What’s interesting about our findings is that with COVID-19, it’s the opposite.”

Distinct immune pathway

These nasal autoantibodies seem to latch onto inflammatory molecules produced by the patient’s own cells early in infection, potentially preventing excessive inflammation. 

The autoantibodies then diminish as recovery progresses, suggesting they serve as an immune response mechanism to keep the inflammatory process balanced. 

This nasal response, in contrast to autoantibodies in the blood, could mark a distinct immune pathway that guards against severe disease.

Immune responses in the nasal cavity 

Earlier studies showed that autoantibodies in the blood often predispose COVID-19 patients to severe illness. However, these studies have largely overlooked the nasal cavity, which is the actual entry and initial infection site for the virus. 

This new study reveals that immune responses in the nasal cavity may function differently, with nasal autoantibodies potentially offering a layer of protection, unlike those found in the blood.

“The key to this puzzle was to look directly at the site of infection, in the nose, instead of the blood,” Ghosn explained. 

“While autoantibodies in the blood were linked to bad prognosis, producing them only in the nose soon after infection is linked to efficient recovery.” This distinction underscores the potential for site-specific immune responses in respiratory illnesses.

New tool to detect local antibodies

To analyze antibodies produced at the infection site in the nose, the Ghosn lab developed a new diagnostic tool called FlowBEAT. 

This biotechnology allows for a more efficient, comprehensive measurement of antibodies in nasal swabs, which could soon have applications for other respiratory illnesses like influenza and RSV. 

Unlike traditional tests, which generally measure only a single antibody type, FlowBEAT can evaluate all human antibody types against dozens of viral and host antigens in one test.

“Historically, the technology to measure antibodies has low sensitivity and is inefficient since they are limited to measuring one or a few antibodies at a time,” Ghosn explained. 

“With FlowBEAT, we can take any standard nasal swab and perform a combination test to simultaneously measure all human antibody types against dozens of viral and host antigens in a single tube.” 

This new technology enables a more sensitive and scalable way to measure nasal autoantibodies, providing valuable insights into infection severity and improving diagnostic capabilities.

Combating respiratory infections more effectively 

The study also opens the door to examining whether this nasal autoantibody response is a common immune defense mechanism in other respiratory infections. 

If similar responses are identified in cases of flu or RSV, this could represent a new understanding of how the body mounts protective immunity against a range of viral infections.

“If this nasal autoantibody response turns out to be a common mechanism to protect us against other viral infections, it can be a paradigm shift in how we study protective immunity,” Ghosn said. 

He envisions this discovery sparking new research avenues and therapeutic strategies for combating respiratory infections more effectively.

More precise treatment decisions 

Following the findings, Ghosn’s team is collaborating with Emory’s patent office to create a diagnostic tool that uses leftover samples from routine nasal swabs taken for COVID-19 tests. 

Such a tool could help healthcare providers assess patients’ immune responses in real time, enabling timely, more precise treatment decisions.

Ben Babcock, a PhD candidate who led the study, emphasized the significance of real-time immune monitoring.

“Imagine if we could capture the immune response in real-time, right in the clinic. A just-in-time test could give physicians and patients the real-time information they need to make faster, smarter treatment decisions,” said Babcock.

If successful, this tool could redefine how respiratory infections are managed in clinical settings, providing patients and healthcare providers with more control over treatment timelines.

Personalized treatment for respiratory infections 

The potential for nasal autoantibodies to influence treatment strategies represents an important step toward personalized respiratory care. 

As Ghosn notes, this discovery challenges traditional perspectives on autoantibodies and offers a promising pathway for real-time diagnosis and treatment options not only for COVID-19 but also for other respiratory infections. 

With further development and clinical testing, FlowBEAT and similar technologies could make it possible to accurately predict disease progression and severity, giving patients a better chance of recovery with minimal complications.

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