The diphtheria vaccine is a crucial immunization that protects against diphtheria, a serious bacterial infection affecting the throat and nose. The vaccine works by stimulating the immune system to produce antibodies against the Corynebacterium diphtheriae bacteria, which can cause severe respiratory issues and complications if left untreated. Typically administered in childhood, the diphtheria vaccine is often combined with other vaccines, such as those for tetanus and pertussis, in a single shot known as the DTaP vaccine. Booster doses are recommended for adolescents and adults to maintain immunity and prevent outbreaks of this preventable disease.