**OPV (Oral Poliovirus Vaccine) Facts**

**Core Concept**
OPV is a live, attenuated poliovirus vaccine administered orally to provide immunity against poliomyelitis. It contains a weakened form of the poliovirus that replicates in the gut, inducing a mucosal immune response and protecting against all three serotypes of poliovirus (PV1, PV2, and PV3).

**Why the Correct Answer is Right**
When administered orally, OPV replicates in the gut, inducing a mucosal immune response that provides protection against poliovirus transmission and infection. This mucosal immunity is essential for preventing poliovirus spread in the community. The vaccine's live, attenuated nature allows it to induce long-lasting immunity, which is critical for global polio eradication efforts. The World Health Organization recommends OPV as the primary vaccine for polio prevention in regions with high poliovirus transmission.

**Why Each Wrong Option is Incorrect**
**Option A:** (insert choice A here) - Incorrect because (insert reason here, e.g. "OPV does not provide long-lasting immunity").
**Option B:** (insert choice B here) - Incorrect because (insert reason here, e.g. "OPV is not administered subcutaneously").
**Option C:** (insert choice C here) - Incorrect because (insert reason here, e.g. "OPV does not contain an inactivated poliovirus").

**Clinical Pearl / High-Yield Fact**
OPV is contraindicated in individuals with immunodeficiency disorders, as the live, attenuated virus may not be adequately neutralized, potentially leading to severe poliovirus infection.

**Correct Answer:** A.