The interdisciplinary team explored the complex causes of long COVID, focusing on the body's adaptive immune response to infection.
Their findings, recently presented at the ESCMID Global microbiology conference in Barcelona, suggest a new path for potential prevention and treatment strategies.
The researchers identified that the absence of antibodies against the nucleocapsid protein of the SARS-CoV-2 virus could double the risk of developing the condition.
The results indicate that current vaccines, which target the spike protein, might be less effective against long COVID, and highlight the need for vaccines that also generate antibodies against the nucleocapsid to provide better protection.
According to the World Health Organization, long COVID is diagnosed when symptoms, which cannot be otherwise explained, persist for at least two months after a three-month period following a SARS-CoV-2 infection.
The nucleocapsid is a viral protein that can disrupt various pathways in cells, promote inflammation, and impair the function of interferons, which play a crucial antiviral role. A lack of antibody production against this protein can potentially lead to prolonged harm from the protein and, as a result, contribute to the development of long COVID.
The researchers collected data from 200 unvaccinated individuals who were experiencing persistent symptoms three months post-infection. Their analysis revealed three distinct long COVID phenotypes—respiratory, cardiac, and psychiatric.
Further studies showed that patients with long COVID had a significantly lower prevalence of IgG antibodies against the nucleocapsid, suggesting that their absence might allow for a prolonged presence of the virus or its components, exacerbating the condition.
"This observation opens potential pathways for therapeutic or preventive measures," said Prof. Piotr Rzymski from the Department of Environmental Medicine at the Poznań Medical University in western Poland.
Speaking in an interview with the portal Nauka w Polsce, Rzymski described long COVID as "an intriguing but difficult to study phenomenon" and elaborated: "Its etiology and the profile of accompanying symptoms are complex. It is essentially a constellation of different ailments with a common cause: the SARS-CoV-2 infection."
He pointed out another challenge with studying long COVID—most scientists rely solely on symptoms reported by patients, which can lead to an overestimation of the phenomenon.
"That's why in our study, we made it objective by using recognized laboratory and biochemical parameters," Rzymski said.
(rt/gs)
Source: PAP