This seems like an easy one to guess - your immune system has been developed over a very long time, is highly complex and has layers of defences everywhere that are all a little different. Training it to look for coronavirus in your muscles is less effective against coronaviruses than training it to look for infections in nasal mucus where said virus is actually trying to enter and exit the body.
This seems like an easy one to guess - your immune system has been developed over a very long time, is highly complex and has layers of defences everywhere that are all a little different. Training it to look for coronavirus in your muscles is less effective against coronaviruses than training it to look for infections in nasal mucus where said virus is actually trying to enter and exit the body.