They used AAV, which is a virus that doesn't cause disease. https://en.wikipedia.org/wiki/Adeno-associated_virus https://en.wikipedia.org/wiki/Adeno-associated

They used AAV, which is a virus that doesn't cause disease. https://en.wikipedia.org/wiki/Adeno-associated_virus https://en.wikipedia.org/wiki/Adeno-associated_virus AAV9 can pass the blood-brain barrier (already), it says there.