This is counter-intuitive for me. Immune system senescence is a thing. Naively I would assume it should be better to get it early, as a younger immune system ha

This is counter-intuitive for me. Immune system senescence is a thing. Naively I would assume it should be better to get it early, as a younger immune system has better odds to react strongly to the antigen, providing long lasting protection. Often the elderly organism doesn't react, or the reaction is too weak, to vaccine stimulation. E.g. see https://www.sciencedirect.com/science/article/abs/pii/S0165247814001187 https://www.sciencedirect.com/science/article/abs/pii/S01652...