I point out, for instance, the smallpox vaccine, of which I heard of no one claiming it is "safe and effective," while at the same time claiming to have subsequently and successfully contracting the disease against which they were inocculated.
But that doesn't contradict the definition at all. Our immune system is called, well, the "immune system", but I'm sure you've been ill before - so clearly it's not actually immune to everything ever. It's a spectrum, not a binary. You can be more or less resistant to certain diseases. Vaccines bring that resistance up, to varying extents.
And, yeah, different diseases are different. Different vaccines are different. If your argument is that the COVID vaccine is not
as good/bad as the smallpox vaccine, meh, sure.
But, to me, that "all or nothing" approach just doesn't work. Should we abandon safety features in cars, just because they fail to prevent
all traffic accident deaths? Should we get rid of lifeguards at beaches and swimming pools? After all, people still drown when they're around.