In the past, why was injection administered in the stomach for dog bite?

ANSWER I: This is the only disease where the vaccine is given after the exposure (post-exposure). Nervous tissue vaccine (NTV), is one of the vaccines administered for dog bite.

This vaccine is prepared from a fixed virus grown in the brain of adult sheep or other animal. The final vaccine is a 5 per cent emulsion of infected sheep's brain containing the inactivated virus.

These viruses do not cause the disease but still retain the antigenecity, i.e., capability of producing the antibodies when injected.

After the bite, about 2-5 ml of the vaccine is administered depending upon the bite severity. More vaccine is administered for a longer duration for severe bites. Bites in the neck, head, face, palm, fingers and multiple wounds are categorised as class three bites.

They require injection for 10 days daily with two booster doses. For such volume of vaccine and duration, the ideal injection site is the anterior abdominal wall. This is preferred as there is a wide area and injection can be given at different points to avoid pain, swelling and discomfort.

Moreover the injections are to be given subcutaneously (below the skin) in the fatty layer. It is a misconception that it is given in the stomach. The needle does enter the abdominal cavity or, for that matter, any of the abdominal organs.

On the abdominal wall skin is held in a fold and elevated. A 1.5 cm needle is used to inject the vaccine in the subcutaneous tissue. After the fold is elevated and such a needle is used there is no possibility of going beyond the subcutaneous layer of the anterior abdominal wall.

This anterior abdominal wall is divided into ten quadrants and injections are given in different quadrants each time. This again results in less pain and swelling.

ANSWER II: The vaccine is given in the stomach region because of the presence of large subcutaneous layer there. Earlier version of this injection needs slower absorption and prolonged activity. Only injection given to a subcutaneous layer can achieve this.

Buttocks and arm region contain larger area of muscle and less of subcutaneous layer.

Hence they are not suitable sites. One more reason is that the stomach region can also accommodate large doses and avoid any complication.

In children despite the subcutaneous layer not being thick and stomach not being large pose no problem as the quantity of injection given is less.

The improved version is a cell cultured vaccine and acts the same way as any other vaccine. In other words it does not require a subcutaneous layer. Hence, it can be given in the buttocks or arm region