Vaccination derives from a word with the root aca meaning cow. Prior to modern medicine people knew they could mediate the likelihood and severity is illness through exposure. They would use cows to develop immunity and then acquire immunity from the cows. So, this demonstrates that immunity can be shared in cases of inoculation. I'm more skeptical, in general, to some of the more modern protein based approaches. I think they don't understand the long term effects (being generous) or may have an agenda.