Well a deadly pandemic wouldn’t need immunity, they’d all die.
Regarding parent; I believe it was known that the measles vaccine wouldn’t protect for life but for a fair amount of time where having to go through the disease would’ve given life lasting immunity.
> 'Herd immunity', also known as 'population immunity', is the indirect protection from an infectious disease that happens when a population is immune either through vaccination or immunity developed through previous infection. WHO supports achieving 'herd immunity' through vaccination, not by allowing a disease to spread through any segment of the population, as this would result in unnecessary cases and deaths.
The new def has a problem though:'protected from ... passing it on'. In my country we are told even after gotten the vaccine we should continue with the measures, because one can still pass it on (meaning it is supposed that the corona vaccine doesnt prevent infection, but prevents all severe cases)
How easy would it be it the future to get a different vaccine course if the one you ended up with was not sterilizing? I assume you would have to pay with your own money, but would you also have to go to a different country and "forget" your immunization record somewhere after you arrive?