Table 1.

Summary of SARS-CoV-2 effects on the BBB and CNS cells

		WT	Alpha	Beta	Delta	Eta	Omicron
Astrocytes
Infection		Non-infected/abortive	Productive	Productive	Productive	Abortive	Productive
Metabolic activity		=	+	+	−	−	=
Cytopathic		No	No	No	No	No	No
Endothelial cells
Infection		Productive	Non-infected /abortive	Productive	Non-infected /abortive	Non-infected / abortive	Productive
Metabolic activity		+	+	+	+	+	+
Cytopathic		Yes	No	No	No	No	Yes
Tight and adherens junctions expression at 6dpi	TJP1	−	−	−	−	=	=
	F11R	−	−	−	−	=	=
	OCLN	=	−	=	−	=	=
	CLDN5	=	+	+	−	=	−
	CDH5	−	−	−	−	=	−
Pericytes
Infection		Abortive	Abortive	Abortive	Abortive	Abortive	Productive
Metabolic activity		+	+	+	+	+	+
Cytopathic		Yes	Yes	Yes	No	No	Yes
Microglia
Infection		Productive	Non-infected / abortive	Non-infected / abortive	Productive	Non-infected / abortive	Productive
Metabolic activity		−	+	=	−	−	=
Cytopathic		Yes	No	No	No	No	No
3D BBB model
Permeability		+	=	=	=	=	±
Glutamate levels		+	+	=	+	+	-

“Infection” (Figs. 1 and 2). Productive: cells are infected productively by the virus (Figs. 1 and 2: infection detected and increased). Abortive: cells are infected by the virus (Fig. 1: infection detected) but no replication (Fig. 2: no infection detected). Non-infected /abortive: cells are either not infected, or infection is not detected because too low (Fig. 1: no infection detected) and no infection is detected in Fig. 2

“Metabolic activity”, “Tight and adherens junctions expression”, “Permeability” and “Glutamate levels” (Figs. 3 and 5). = : no change. + : increase. -: decrease. ± : slight increase

“Cytopathic” (Fig. 4). Yes: virus is cytopathic for the cells. No: virus is not cytopathic for the cells