When I studied Microbiology under an Air Force Virologist I was taught a vaccine has the eradicated “bones” or dead virus bodies in it to cause the immune system to form anti-bodies against that specific virus.
I suppose you could claim a Cow was a bull, but the lack of balls would prove the lie.
I suppose you could claim a bull was a cow, but the lack of teats would prove the lie.
Personally I would not want to be the one tried to milk the bull.
You could claim a skunk was a kitty cat but you not going to get me to pick it up and try to pet it!
The Ole Dog!