. 2024 Jan 30;5(1):81–94. doi: 10.1089/neur.2023.0067

Table 1.

List of Pathomechanisms Suspected in the Development of Long-COVID/PASC and Their Potential Effect on the Outcome After Various Severities of TBI

*Pathomechanism(s) (selected)*	*Level of evidence in the pathomechanism of long-COVID/PASC*	*Potential influence/effect on outcome after*
*Pathomechanism(s) (selected)*		*miTBI*	*MoTBI*	*sTBI*
Direct
Direct viral invasion and/or viral reservoirs in the CNS	Low/uncertain^{67,68,244,245}	?	?	?
Definition: presence of the virus and/or viral particles in cells of the CNS	Low/uncertain^{67,68,244,245}	?	?	?
Indirect
Endothelial damage/dysfunction/(micro)vascular injury	Moderate to high^{64,70,75–77,93}	+++	+++	+++
Definition: abnormal vascular functions, more reactive endothelial phenotype, injury, blockage of small vessels including capillaries	Moderate to high^{64,70,75–77,93}	+++	+++	+++
Abnormal coagulation	High (after severe COVID-19)^79,246,247	+++	+++	+++
Definition: disruptions in the body's ability to control blood clotting	High (after severe COVID-19)^79,246,247	+++	+++	+++
Inflammation	High (after severe COVID-19)^{81,89,107,248–250}	+/–	++	+++
Definition: maladaptive immune response	High (after severe COVID-19)^{81,89,107,248–250}	+/–	++	+++
Abnormal immunometabolism	Moderate^84–87,251	+/–	++	+++
Definition: changes in intracellular metabolic pathways of immune cells that alter their functionality	Moderate^84–87,251	+/–	++	+++

PASC, post-acute sequelae of SARS-CoV-2 infection; TBI, traumatic brain injury; CNS, central nervous system; COVID-19, coronavirus disease 19.