There are (I am sure, rhetorical) legal forms, in which the doctor is prompted to acknowledge each of the admitted ingredients, and it's known side effects. Many versions of this gag, online.
I had started asking childish questions, myself, when cross species resistance had been mentioned, in school; it is partially made from (other) animals.
Also, how is viral material killed or attenuated or living, just-enough, so as not to cause disease. This was just asked, out of curiosity, as toward a teacher; there was no ruse in mind. It was said that viruses are not living, in the ordinary sense. Then, how is it dead, I wondered.
A relative had been receiving chemotherapy. So, there were warnings to the effect of radioactivity in the toilet and shower. As I researched more, about shots, in general, I learned that vaccinated people can become asymptomatic (if they are lucky) carriers, shedding virions, from days to months. It has been speculated that patient zero, in the Disneyland measles outbreak, had been vaccinated.
It is not an example of magical thinking, to suppose that inflammation, or critical illness, can result in neurological damage, Bad batches have been reported in mainstream news.