**Core Concept**
Risk of HIV transmission after needle prick injury depends on the viral load of the source patient, the depth and proximity of the injury, and the promptness and effectiveness of post-exposure prophylaxis (PEP). The risk is higher if the needle was used for vascular access or if the source patient has a high viral load.

**Why the Correct Answer is Right**
The risk of HIV transmission after a needle prick injury is estimated to be around 0.3% if PEP is administered promptly. This risk is significantly lower than the risk of HIV transmission from other types of blood-borne exposures, such as mucocutaneous exposure. The effectiveness of PEP in preventing HIV transmission is due to the antiretroviral medications' ability to suppress viral replication and prevent the establishment of a persistent infection.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the risk of HIV transmission after a needle prick injury is not 1-2%. The actual risk is significantly lower due to the effectiveness of PEP.

**Option B:** This option is incorrect because the risk of HIV transmission after a needle prick injury is not 5-10%. The actual risk is lower than this estimate, and PEP can significantly reduce the risk of transmission.

**Option C:** This option is incorrect because the risk of HIV transmission after a needle prick injury is not 20-30%. The actual risk is significantly lower than this estimate, and PEP can prevent HIV transmission in most cases.

**Clinical Pearl / High-Yield Fact**
Prompt administration of PEP within 72 hours of a needle prick injury can significantly reduce the risk of HIV transmission. It is essential to identify the source patient's HIV status and provide PEP promptly to minimize the risk of transmission.

**Correct Answer:** D. 0.3%