False regarding OPV-
**Core Concept**
OPV (Oral Poliovirus Vaccine) is a live attenuated vaccine used for the prevention of poliomyelitis. It contains a weakened form of the poliovirus, which stimulates an immune response without causing the disease.
**Why the Correct Answer is Right**
The correct answer is related to the immunogenicity of OPV. OPV is a live attenuated vaccine, which means it contains a weakened form of the virus that can cause a mild infection in the gut, thereby inducing an immune response. This immune response provides long-term protection against poliomyelitis. The attenuation of the virus is due to multiple mutations in the viral genome, which reduce its virulence.
**Why Each Wrong Option is Incorrect**
**Option A:** OPV is administered only to children under 5 years of age. This statement is incorrect because OPV can be administered to children of any age, although it is most effective in young children.
**Option B:** OPV is not effective against non-polio enteroviruses. This statement is incorrect because OPV can provide some cross-protection against other enteroviruses, although its effectiveness against non-polio enteroviruses is limited.
**Option C:** OPV can cause vaccine-associated paralytic poliomyelitis. This statement is incorrect because OPV is extremely rare and has been largely eliminated through the use of the vaccine.
**Clinical Pearl / High-Yield Fact**
It's essential to note that OPV is not recommended for use in areas where polio has been eradicated, as it can potentially lead to the re-emergence of the disease.
**Correct Answer:** D.