If you squint you could say that viruses are already doing that. A lipid bilayer is a key component of several kinds of membranes. All of our cells have a lipid

If you squint you could say that viruses are already doing that. A lipid bilayer is a key component of several kinds of membranes. All of our cells have a lipid bilayers separating the inside from the outside. The corona virus is also built from these same lipids, which is why it's vulnerable to soap. Anyway, I think the important thing that the other commenter was saying is that mRNA needs to be carefully packaged to be medically useful. You can't inject pure RNA as a vaccine because not only is the mRNA going to be quickly degraded before it gets anywhere but if the immune system sees any RNA floating around by then it kicks itself into a frenzy because free-floating RNA is usually a sign that something nasty is afoot.