Table 1.

Viral vectors and their main properties

Vectors	Vector yield (transducing units mL1)	Inflammatory potential	Tropism re-targeting	Entry pathway	Vector genome forms	Transgene expression	Genotoxicity	Shedding
Retrovirus	Moderate (1010)	Low	Dividing cells	Receptor-binding, membrane fusion	Integrated	Long term (years)	Integration might induce oncogenesis	Low
Lentivirus HSV-1	High (1012)	High	Broad Neurons	Receptor-binding, membrane fusion	Episomal	Transient	Low	ND
Adenovirus	High (1012)	High	Broad	CAR-mediated endocytosis endosomal escape	Episomal	Short term (weeks)	Low	Moderate
AAV	High (1012)	Low	Broad	Receptor-mediated endocytosis endosomal escape	Episomal (90%) Integrated (10%)	Medium to long term (year)	Should not be underestimated. Needs more investigation	Moderate