If, having had COVID19, POTUS is now immune and can't get it again and can't give it, that puts vaccinators in a bit of a bind. Immunity via vaccination is achieved by injecting a weakened version of the disease. Vaccine manufacturers won't admit the possibility of "shedding" i.e. a recently vaccinated person causing an outbreak of the disease they have just been innoculated against.
If they argue that POTUS can still transmit COVID even though he now has natural immunity, then they have to admit that their vaccinations can actually cause disease outbreaks as has been the case in Africa with polio vaccinations causing polio outbreaks. If they agree that having acquired natural immunity he cannot transmit the disease, then all those COVID positive test results must indicate a widespread, naturally acquired immunity which obviates a need for vaccinations.