NATURAL IMMUNITY is more powerful and broad based than a vaccine. This is proven science. Someone who has gotten chicken pox, for example, does NOT get vaccinated for it - if you've gotten the actual disease and recovered, you don't need a vaccine. The vaccine protects you, but natural immunity provides an even better protection.

Now, in the case of the flu, there are seasonal variants and so we do give vaccines to vulnerable people. HOWEVER, we don't force everyone to take it even though the flu is contagious, because otherwise young and healthy people are not likely to be hospitalized due to the flu (the elderly often are) and also - if you get the flu and recover, your natural immunity is already primed to recognize and fight off other variants of the flu.

The first time a population is introduced to a new disease, death rates are quite high - however, over time, the death rates are much smaller even if they were exposed to different variants of the disease. This is why Native Americans originally had a huge die-off when introduced to Europeans but after a couple of generations this was no longer the case.

This is actually based on science. You can read scientific journals in the fields of epidemiology to learn about this if you are actually intellectually curious vs. just wanting to march in lockstep with current opinion. If you disagree with me, please cite actual scientific research that denies natural immunity vs. merely citing an opinion.