Tetanus vaccine. Gloved fingers holding an ampoule of tetanus toxoid, a vaccine for tetanus. Tetanus is caused by a toxin produced by spores of the bacterium Clostridium tetani in infected wounds. The vaccine consists of a modified version of this toxin, a toxoid, and is injected into muscle tissue, the site of the toxin's effect. This stimulates the immune system, protecting against future infection. Children are routinely vaccinated against tetanus but booster vaccinations are recommended every 10 years in adults. Rubber gloves help to maintain sterile conditions.