**Core Concept**
Human immunoglobulin is a preparation of antibodies that provides immediate, short-term protection against specific infections. It is used to prevent or modify the course of diseases caused by viral and bacterial pathogens.

**Why the Correct Answer is Right**
Measles is a viral infection caused by measles virus, and it is not typically treated with immunoglobulin. In fact, measles immunoglobulin is contraindicated in measles infection, as it can suppress the immune response and mask the disease, potentially leading to vaccine failure. Immunoglobulin is not a substitute for vaccination, and its use in measles is not supported by evidence. The other options, such as Hepatitis B, Rabies, and chickenpox, are all conditions where immunoglobulin may be used to provide immediate protection.

**Why Each Wrong Option is Incorrect**
**Option B:** Hepatitis B is a viral infection where immunoglobulin is used to provide immediate protection, particularly in newborns of infected mothers. It helps prevent the transmission of the virus.
**Option C:** Rabies is a viral infection where post-exposure prophylaxis with immunoglobulin is a critical component of treatment. It helps neutralize the virus and prevent the development of rabies.
**Option D:** Chickenpox is a viral infection where immunoglobulin is used to provide immediate protection, particularly in high-risk individuals such as immunocompromised patients. It helps reduce the severity and duration of the disease.

**Clinical Pearl / High-Yield Fact**
Immunoglobulin should not be used as a substitute for vaccination, and its use should be guided by specific indications and contraindications. Always consult the latest guidelines and recommendations from reputable sources, such as the World Health Organization (WHO) or the Centers for Disease Control and Prevention (CDC).

**✓ Correct Answer: A. Measles**