Innovative Approach to Treat Long COVID by Targeting the Epipharynx

The long-term effects of COVID-19, known as long COVID, continue to challenge healthcare systems worldwide, impacting a significant number of survivors. Recent research from Japan has shed light on a potential treatment strategy aimed at mitigating these persistent symptoms by focusing on the epipharynx, a region of the pharynx located behind the nasal cavity.

A research team at the Oral Medicine Research Center, Fukuoka Dental College, led by Kensuke Nishi and Akira Watanabe, has discovered that the epipharynx is a critical site for chronic inflammation caused by residual SARS-CoV-2 RNA. Employing advanced molecular mapping technology called Visium HD spatial transcriptomics, they conducted a high-resolution gene expression analysis of the epipharynx in patients suffering from long COVID, with their findings published in Scientific Reports.

This region has been identified as a primary target for upper respiratory infections, including COVID-19. The research revealed that SARS-CoV-2 viral RNA can persist in the epipharynx for over six months post-infection, activating local immune responses that may contribute to the chronic symptoms associated with long COVID, such as fatigue, persistent cough, dizziness, and cognitive difficulties.

The investigators noted that the residual viral RNA does not simply represent leftover material from the initial infection; instead, it plays an active role in triggering immune responses and inflammation. Given the anatomical challenges of observing the epipharynx without endoscopic techniques, the researchers advocate for increased clinical and research focus on this area as a potential target for treatment.

To explore treatment options, the team investigated epipharyngeal abrasive therapy (EAT), a technique traditionally used in Japanese otolaryngology since the 1960s. This method involves swabbing the epipharynx with a 1% zinc chloride solution. After a treatment regimen lasting three months, patients reported significant symptom improvement. Analysis post-treatment indicated a notable reduction in viral RNA levels and a decrease in inflammatory markers, suggesting that EAT effectively modulates immune responses and aids in tissue repair.

Furthermore, spatial transcriptomic analysis post-EAT revealed that this therapy not only helps in the removal of damaged epithelial cells but also downregulates overactive immune pathways, highlighting its dual role in promoting healing and immune modulation.

While the study had a limited sample size, it represents a promising step toward understanding the biological mechanisms underlying long COVID. The researchers have indicated that a multi-center clinical trial is currently underway to validate the efficacy of EAT in a broader population.

As estimates suggest that between 31% and 69% of individuals recovering from COVID-19 experience lingering symptoms, this study signifies a crucial advancement in identifying the epipharynx as a reservoir for viral RNA and potential immune disruption. The findings open new possibilities for targeted therapies aimed at treating long COVID effectively.