eli5- why do you get a tetanus shot even after you cut yourself with something rusty?

Question

If shots (vaccines) are supposed to simulate the infection before getting the real thing, why does it work after you get the actual virus in your body

In: 1

Answer 1

there are two kinds of tetanus shots.

One kind is the tetanus vaccine. you have to get that kind before you get injured, as a precaution. That’s the kind of vaccine you’re describing, which primes the immune system. it takes at least a week (usually two) for a vaccine to fully activate your immune system.

The other kind is the tetanus anti-toxin. it’s basically purified antibodies that will neutralize the tetanus toxin. it works right away, because your body doesn’t have to make the antibodies. But it’s temporary. The antibodies only stay in your system for a few days or weeks.They make anti-toxin by vaccinating some other animal, usually a horse. the horse becomes immune to tetanus toxin, and we collect blood from the horse which contains antibodies against tetanus toxin. the antibodies are purified and we use that as anti-toxin.