I can see the spike protein added to all the common cold viruses, if the capsid is big enough, so we would get a dose of capsid with every cold (less if we have a flu shot that hits). They can also use any spreadable virus that does not give long immunity (since we need new spike antigen exposure every year it seems, since that immunity wanes).
What could go wrong? The spike alone carries no problems. it is the associated virus executibles that unpack from Covid-19 after entry that do the harm.
It is a worthwhile approach but the path will be long as they will have to make sure there is no risk of 'gain of function'
My impression of spike attachment, via mediator, to the ACE2 is for cellular entry. I am not sure if this will exhaust the other ACE2 on other cells. That said a saturation level of spike in the blood so all cells lose spike in all areas is very unlikely, as this would, in all certaintly, be lethal??
A full blown infection - does it ever reach the level of ACE2 exhaustion - or are there many cells no reached? Heart cells - death of many heart cells would be a problem?
