What are toxoids?

A substance that has been treated to destroy its toxic properties but retains the capacity to stimulate production of antitoxins, used in immunization.

A toxoid vaccine is effective against illness caused by bacteria by using harmless varieties of the toxins caused by the bacteria. For example, the diphtheria bacteria (Corynebacterium diphtheriae) can make people seriously sick by infecting the respiratory system and releasing poisons. The diphtheria vaccine is created by inactivating diphtheria toxins with a formaldehyde-based substance called formalin. The vaccine enables a person's body to learn to fight against the toxin, preventing harm from a diphtheria infection. Tetanus is another illness prevented with a toxoid vaccine.