>>11514841In principle, perhaps. In practice, immune system has to learn. Low-level exposure to pathogens in the environment and vaccines fulfill that function. Among pathogens well-adapted to infect humans, it an arms race between the host evolution of innate immunity (that is active without need for the aforementioned learning) and the pathogen evolution to cause continued infections. Sometimes this co-evolution results in the pathogen becoming asymptomatic; that removes the evolutionary pressure from the host to develop immunity. HSV-1 is asymptomatic most of the time and infects around half of the world population. It is one of the most evolutionary successful human pathogens.
There is also the problem that an active enough immune system could attack the own body (auto-immune disease) and normal intestinal flora. You can modulate your immune system activity with some pharmaceuticals. Increase with estrogens, decrease with glucocorticoids. Do not do this unless you have researched the consequences in the *scientific* literature.
>>11514845It is more or less socially acceptable until the COVID-19 scare passes.
