It is not true that kissing boosts immunity; kissing may lead to an exchange of oral flora that activates the immune system. Immunity is the body’s defense system, including the ability to recognize and destroy external invaders, and to deal with the body’s aging, apoptotic, damaged, mutated, and infected cells. Immunity also includes non-specific and specific, non-specific immunity is born with, specific immunity is generated later, their own infection with viruses, the body generates relevant antibodies, and by the body’s immune system memory. Kissing will lead to mutual exchange of pathogens in the mouths of both kissing parties, which may lead to the spread of disease and activate the immune system to remove pathogens, but will not lead to an increase in their removal ability. Kissing will not improve immunity. Ways to improve human immunity include exercise, proper diet, vaccination, and regular work and rest.