St Vincent's researchers discover biomarker for Long COVID

27 Jun 2023

St Vincent’s researchers are the first in the world to have identified the biomarker for Long Covid, particularly in relation to cognitive impairment. This discovery will facilitate the development of targeted drug treatments, improve monitoring of the disorder, and help to better determine appropriate timing for treatment.

This discovery and the possibility of treatments to come is great news for the estimated 65 million people worldwide who are living with Long COVID.

The study assessed the prevalence, natural history and cause of long COVID cognitive impairment and function, specifically in unvaccinated patients, following mild to moderate (not requiring hospitalisation) COVID-19 disease.

Researchers found that almost half of the research participants experienced cognitive impairment at least once during the 12 month study period, with up to 26% presenting with impairment to such an extent that it impacted their capacity for returning to work.

Measured at 2, 4 and 12 months post COVID-19 infection, there was prolonged activation of the Kynurenine Pathway in patients experiencing cognitive difficulties. Moreover this elevation, associated with brain injury, was detected with no other blood abnormalities and an absence of pre-existing mental health issues, medical comorbidities or other respiratory dysfunction that could otherwise cause impairment.

Based on these findings, the team were able to determine this unique biomarker, associated with Kynurenine Pathway activation, as the likely cause for cognitive decline in people with Long COVID.

The St Vincent's team were also able to document cognitive impairment as a relatively common condition post-acute COVID-19 infection that persists at 12 months. Offering further proof that relying on disease severity to estimate COVID-19 disease burden would result in a significant underestimation, since the effects of even mild to moderate COVID-19 infection can continue to be disruptive to patients’ lives, impeding their ability to function at pre-COVID levels for 12 months and longer, post-infection.

Click here to read the full research paper, led by Professor Bruce Brew, St Vincent’s Neurologist, as published by the Journal of the American Neurological Association.