This is fraught with possibilities for evil doers. It could be viral or vaccine shedding depending on the maker's goal?

There is an element of this concept of "contagious vaccines" already in the Covid 19 vaccine. Perhaps a test. After getting the jabs, a cousin had an instance of shedding to her partner who was not getting vaxxed. Scared him to death the reaction was so bad and he thought he had prostate cancer. Did not, thank God.