Tetanus needs an anaerobic environment inside your body to create the toxin that causes the illness. That is why the rusty nail is always used as the example, not because of the rust or dirt, but because it would be a deep puncture wound. So basically, if the wound has bled, it's not going to be a problem. Even if you have a deep puncture that is a potentially anaerobic environment, the chances of getting tetanus are extremely slim. Plus, if you go to get a shot because of a wound, it's too late for the shot to prevent tetanus (if you're assuming the vax even works the way it's supposed to). So the standard practice of vaxxing people who've ended up in the er due to a wound is nothing but nonsense.

Edit: The tetanus bacteria can even be found in the human gut. So it's not something that should be feared so much, as if all it takes is contact with the bacteria to cause serious illness. It requires the bacteria plus the perfect environment to become a problem.

Tetanus needs an anaerobic environment inside your body to create the toxin that causes the illness. That is why the rusty nail is always used as the example, not because of the rust or dirt, but because it would be a deep puncture wound. So basically, if the wound has bled, it's not going to be a problem. Even if you have a deep puncture that is a potentially anaerobic environment, the chances of getting tetanus are extremely slim. Plus, if you go to get a shot because of a wound, it's too late for the shot to prevent tetanus (if you're assuming the vax even works the way it's supposed to). So the standard practice of vaxxing people who've ended up in the er due to a wound is nothing but nonsense.