For post-exposure prophylaxis, dose of human rabies immunoglobulin is: September 2007
**Core Concept**
Human rabies immunoglobulin (HRIG) is a post-exposure prophylaxis (PEP) measure used to neutralize the rabies virus in individuals exposed to infected animals. It provides immediate, short-term protection against rabies while the individual's immune system is stimulated to produce antibodies against the virus.
**Why the Correct Answer is Right**
The recommended dose of human rabies immunoglobulin is 20 IU/kg body weight, administered intra-muscularly as soon as possible after exposure. This dose is sufficient to neutralize the virus and prevent its spread to the central nervous system. The dose is typically administered in a single site, such as the deltoid muscle, to minimize the risk of local reactions.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the dose of HRIG is not 10 IU/kg. While this dose may be effective, it falls short of the recommended dose and may not provide adequate protection against the virus.
**Option B:** This option is incorrect because the dose of HRIG is not 40 IU/kg. While this dose may provide excessive protection, it is not the recommended dose and may increase the risk of adverse reactions.
**Option C:** This option is incorrect because the dose of HRIG is not 15 IU/kg. While this dose may be close to the recommended dose, it is not sufficient to provide adequate protection against the virus.
**Clinical Pearl / High-Yield Fact**
HRIG should be administered as soon as possible after exposure, ideally within 7 days. It is essential to administer HRIG in conjunction with a series of rabies vaccinations to ensure long-term protection against the virus.
**Correct Answer: B. 40 IU/kg body weight.**