Question

1. A young girl who had never been immunized to tetanus stepped on a rusty nail and got a deep puncture wound. The doctor cleaned out the wound and gave the child an injection of tetanus antitoxin.

1. Why was antitoxin given instead of the tetanus vaccine?
2. If the girl receives no further treatment and steps on a rusty nail again 3 years later, will she be immune to tetanus?

Answer 1

A) A vaccine creates a memory of antigen receptors in the immune system in response to which antibodies are formed.

So when the disease causing antigen comes in contact with vaccinated person, the immune system forms the respective antibodies and the person is notnaffected by the disease.

But in this case,the girl is not previously immunized..thus passive immunization is needed.

Passive immunization refers to transfer of antibodies from a person who already have those antibodies against the toxin caused by Clostridium tetanii .i.e ready made antibodies are injected to avoid the toxin to cause the disease.

Thus antitoxin is given to provide passive immunity.

This antitoxin is purified proteins containing antitoxic antibodies in plasma or serum of healthy horses who are immunized against tetanus.

B) Passive immunity is not permanent..It lasts for almost only 3 to 4 months.

Thus the girl will not be immune to tetanus if she is not given the further treatment.

Thus she should be given the tetanus vaccination after her wound heals.