The immune system peaks around puberty, and then declines with age after that, ending up degenerating quite a bit. However, with the immune system being responsible for performing so many vital tasks within the body, it is important to understand the connection between aging and immunity, so... The immune system peaks around puberty, and then declines with age after that, ending up degenerating quite a bit. However, with the immune system being responsible for performing so many vital tasks within the body, it is important to understand the connection between aging and immunity, so...