Stepping on a Rusty Nail Causes Tetanus

Yet another wives tale that plagued many a mother and child is that surrounding the fear of not getting a tetanus vaccine would lead inevitably to a child getting tetanus from stepping on a rusty nail. Setting aside for a moment the likelihood of stepping on a rusty nail to begin with is there any validation to this claim, or is it truly just an old wives tale?

The Rusty Nail Wives Tale

The basic idea here is that stepping on a rusty nail—or rather, the wound resulting from stepping on a rusty nail—will result in tetanus, what is sometimes referred to as “lockjaw.” Tetanus is a nasty disease that causes the stiffening if muscles and does affect the face; the jaws can’t be opened, hence the nickname. The source of this wives tale comes from World War II, where many soldiers were infected with and died from tetanus, mostly infected via deep puncture wounds. Hence this wives tale is more of a half- truth; the wounds from stepping on a nail can cause tetanus, but the rust has nothing whatsoever to do with it.

Infection

Tetanus comes from infection breeding where there is little to no oxygen, so a deep puncture would certainly qualifies as a potential danger. It is the dirt that may have been on the puncturing instrument that can lead to infection, so a nail needs no rust to lead to tetanus, just dirt. In the trenches of WWII there were plenty of sharp, dirty objects that would qualify, and after the tetanus vaccine was created and introduced, the suffering and deaths dropped sharply. Here was a case where the tetanus vaccine made a lot of sense, as the soldiers were in a very hazardous environment with a high chance of contracting the disease. Do today’s children have the same odds?

Should You vaccinate?

Ultimately the decision a parent makes about whether or not to vaccinate their child should be made after proper research with qualified sources. Certainly there are less chances of sustaining deep, dirty puncture wounds in every day life than a soldier in the trenches of The Big One, but the possibility exists. So, too, do proper antibiotic treatments for treating deep puncture wounds—thus if you opted out of a tetanus shot when you were young there are still treatment options if a wayward rusty nail finds your foot.

Why the Link between Rust and Tetanus?

How did “rusty nail” get linked up with infecting lockjaw in the first place? Likely it came about as stories of soldiers suffering and dying from tetanus were released, and as is common with many fallacies and wives tales, correlation implied causation. A good filter of logic to apply to this—and many—situation is “correlation does not imply causation”. This simply means that just because two events occurred at roughly the same time, there does not mean a cause and effect relationship exists. In this case a person steps on a rusty nail and develops tetanus; it is easy to say the rusty nail caused the tetanus, but in reality the dirty wound not properly treated caused the lockjaw, not the rust on the nail.