According to the CDC, only 57.2% of adults are protected against tetanus. It drops to only 44.1% for those over age 65. This is surprising given the high fatality rate for the disease and the prevalence of the C. tetani bacteria in the environment.
The tetani bacteria produce spores that are very difficult to kill and are found in the soil and intestines and *** of horses, sheep, cattle, dogs, cats, rats, guinea pigs, and chickens. The likelihood of tetanus is greatest following deep, dirty puncture wounds where there is little bleeding and an absence of oxygen. But tetanus has also occurred following other injuries such as burns, scratches, slivers, animal bites, body piercing, and tattooing. In recent years, minor wounds have caused more cases of tetanus than major wounds. This is probably because more severe wounds are better managed.