NEW evidence from a prospective cohort study suggests that elevated plasma phosphorylated tau (pTau-181) may be a critical biomarker in patients experiencing neurological post-acute sequelae of COVID-19 (N-PASC), particularly among essential workers.

N-PASC and pTau-181: Key Biomarker Insights

Researchers followed 227 essential workers who developed COVID-19 and subsequently experienced N-PASC, comparing them with 227 demographically matched controls who either recovered without neurological symptoms or did not contract the virus. Using single molecular analysis, the study measured changes in neurological biomarkers including pTau-181, glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), and amyloid beta (Aβ40/42 and total Aβ burden, IAB).

Significant Increases in pTau-181 Post-COVID

The findings revealed a striking 59.3% increase in plasma pTau-181 levels among participants with N-PASC following COVID-19 onset, with the greatest elevations in those reporting persistent central nervous system symptoms, commonly described as brain fog, cognitive difficulties, and loss of taste or smell, lasting 18 months or more. In contrast, GFAP and NfL reductions were linked to peripheral neurological symptoms, suggesting distinct biomarker profiles depending on symptom localisation.