## **Core Concept**
The question tests knowledge of vaccine administration in immunocompromised individuals, specifically children with AIDS. It requires understanding of live attenuated vaccines and their implications in immunocompromised hosts.

## **Why the Correct Answer is Right**
The correct answer, **D. IPV (Inactivated Poliovirus Vaccine)**, is appropriate for an AIDS-positive child because it is an inactivated vaccine. Inactivated vaccines do not contain live viruses, making them safer for administration to immunocompromised individuals, including those with AIDS. IPV provides immunity against poliovirus without the risk of vaccine-induced disease.

## **Why Each Wrong Option is Incorrect**
- **Option A:** BCG (Bacillus Calmette-Guérin) is a live attenuated vaccine. Live vaccines are generally contraindicated in immunocompromised individuals, including AIDS-positive children, due to the risk of vaccine strain infection.
- **Option B:** OPV (Oral Poliovirus Vaccine) is a live attenuated vaccine. Like BCG, it poses a risk to immunocompromised individuals and is not recommended for AIDS-positive children.
- **Option C:** Varicella vaccine is also a live attenuated vaccine. It is contraindicated in individuals with significant immunodeficiency, including those with AIDS, due to the risk of severe vaccine-related complications.

## **Clinical Pearl / High-Yield Fact**
A crucial point to remember is that live vaccines are generally contraindicated in immunocompromised patients, whereas inactivated vaccines are safe. Always assess the immune status of a patient before administering vaccines, especially in cases of HIV/AIDS.

## **Correct Answer: D. IPV (Inactivated Poliovirus Vaccine)**