I believe you are correct in that the strand of RNA that modern science hypotheses causes viral diseases that are spread by close contact / airborne droplets does nothing of the sort. It is likely a leftover fragment from when the body carries out a routine detox.

Now, as to whether viruses exist - I believe they do. However, they are psychological in nature and spread by fear. Given that the imagination has the power to heal the physical body, should the mind become polluted with crap and bad ideas, it also has the power to cause great harm and even to kill. Bad health and detox onset can be spread by peer pressure and the power of influence. If a doctor tells you you are going to die, most folk just get on with following orders.

The irony of this truth is that a muzzle will stop you getting ill if you believe it will. Sadly, most of those who've donned the face-rag are weak-willed and don't have the power of belief. They also succumb to peer-pressure very readily, which means when a friend gets ill, they get ill, rending their mask useless.