the main trophic target of this virus is lung tissue. a nebulizer would deliver the mRNA-Fc complex to the lung tissue.

the other way around would look a lot like a classic vaccine delivered by injection, and encapsulate the mRNA into a vesicle that targets antigen presenting cells in the lymphatic system which then presents the mRNA product as an antigen-MHC complex to specify what antibody to generate.

Deliver mRNA, or a protein?

both or either dependent on the therapeutic strategy.

this is also something that is not limited to corona virus, this is the basis of a recombinant vaccine that can be adjusted for any antigen.

Cool. I was thinking about immunotherapy like IL proteins.. sometimes they are injected and sometimes infused, I don't know why.

it depends on the targets distribution, is it diffuse in the body or is it localized to a certain tissue type.