You need these proteins to interfere with viruses before they enter cells, so that part is probably fine.

Where the virus can go the antiviral can go too (because it's much smaller, only targeting a smaller protein spike on the surface of the viral envelope).

https://en.wikipedia.org/wiki/Coronavirus#/media/File:3D_med... [the N protein is supposedly the nucleocapsid, which is basically/maybe another envelope around the RNA]