Rabies immunoglobulin

Rabies, a viral zoonotic neglected tropical disease, poses a severe public health threat in over 150 countries and territories, primarily in Asia and Africa. Each year, this disease results in tens of thousands of fatalities, with children under 15 accounting for 40% of these deaths. Rabies infects mammals and is spread to humans and other animals by contact with saliva, most commonly through bites and scratches. Worldwide, nearly all human rabies cases are caused by dog bites and scratches. However, in the United States, bats are now the primary source of human rabies due to the diligent vaccination of dogs against rabies.

Rabies immunoglobulin (RIG) is a medication made up of antibodies against the rabies virus. It is used to prevent rabies following exposure. It is given after the wound is cleaned with soap and water or povidone-iodine and is followed by a course of rabies vaccine. It is given by injection into the site of the wound and into a muscle. It is not needed in people who have been previously vaccinated against rabies.

Common side effects include pain at the site of injection, fever, and headache. Severe allergic reactions such as anaphylaxis may rarely occur. Use during pregnancy is not known to harm the baby. It works by binding to the rabies virus before it can enter nerve tissue. After the virus has entered the central nervous system, rabies immunoglobulin is no longer useful.

The use of rabies immunoglobulin in the form of blood serum dates from 1891. Use became common within medicine in the 1950s. It is on the World Health Organization's List of Essential Medicines. Rabies immunoglobulin is expensive and hard to come by in the developing world. In the United States it is estimated to be more than US$1,000.00 per dose, and around £600 in the United Kingdom. It is made by isolating rabies immunoglobulin from donated blood plasma of humans or horses who have high levels of the immunoglobulin. The equine preparation is less expensive but has a higher rate of side effects.