U.S. scientists developing nasal spray to prevent COVID-19

Not likely to be an useful option, AAV is quite inneficient so large amounts are needed to make cells produce proteins, so it becomes prohibitively expensive to make doses. It also quickly stimulates immune responses againts itself, so only the first dose is effective, meaning that as soon as the cells with the new DNA are lost (very quickly for cells of the nose and throat) trying to use the AAV again will not be effective.

And finally it is horribly complicated to demonstrate that viruses transporting DNA are safe, because differently from the mRNA vaccines the DNA can actually be incorporated into the genome of the cells and produce unexpected results including the possibility of cancer.

So it would be a very expensive therapy useful only for a short time, nobody knows how effective it would be and you could not repeat the dose, if you add the possibility of serious side effects it is clear that the costs and dangers outweigh the benefits. This is the reason why gene therapy using DNA is reserved to lethal diseases that can be cured with a single dose, like the spinal muscular dystrophy, risks and cost are still high, but the benefits are much higher, so it can be justified.

Yes, of course, a working nasal spray agains corona...and the updated version also brings back all your hair volume from younger years, fights cellulite completely away and whitens all your skin problem zones...lol