The way vaccines work is by exposing people's immune systems to small, less toxic amounts of a pathogen, letting the body produce antibodies to it so that it will be better able to repel the enemy when it next encounters it.
疫苗的運作基礎是，藉由讓身體的免疫系統接觸少量且經過減毒的致病微生物，讓人體產生抗體，好在下一次敵人真正來襲時擊退它們。