It's a different type of virus. We have never, ever, successfully achieved the level of immunity against a rapidly mutating airborne virus as we have with SARS-CoV-2. Our greatest successes, Polio and Smallpox, were both extremely stable and without animal reservoirs, making vaccination much more straightforward.
You're demanding perfection and insisting that anything that falls short is worthless. That makes no sense.
You're demanding perfection and insisting that anything that falls short is worthless. That makes no sense.