“some are under the illusion that we would be safe if all of our compatriots get vaccinated. It’s false.”

Of course vaccines are effective but not 100% effective and no one measure will by itself eradicate the pandemic.

I think things will make more sense to you if you think in probabilities and not absolutes.

Vaccines REDUCE contagion, as do masks and social distancing. And other factors play a role.

The same is true of climate destruction. If we sharply reduce burning fossil fuels, this will help but not fix the climate by itself. The same is true for almost every complex challenge.