Immunisation: circulating vaccine-derived poliovirus: practice question

A Pediatrics question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Pediatrics · Immunisation: circulating vaccine-derived poliovirus

Sample item

Three unimmunised children in a low-coverage area develop flaccid paralysis. Stool isolates are Sabin-derived strains with genetic changes that have regained neurovirulence, and sequencing shows the viruses are linked and have spread person to person in the community. Which term applies?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Circulating vaccine-derived poliovirus

Vaccine-derived polioviruses arise when attenuated Sabin virus replicates for a long time and reverts. When linked isolates show person-to-person spread in a community with low immunity, they are classed as circulating VDPV and can cause outbreaks. VAPP is sporadic and affects a vaccine recipient or close contact without community spread.

Option by option

  • A. Immunodeficiency-associated vaccine-derived poliovirus

    This type arises from prolonged excretion by an immunodeficient individual, with no chain of community transmission.

  • B. Circulating vaccine-derived poliovirus (correct)

    Correct. Linked, reverted vaccine-derived isolates spreading in the community define cVDPV.

  • C. Wild poliovirus type 1 infection

    Isolates here are Sabin-derived, not wild virus.

  • D. Vaccine-associated paralytic poliomyelitis

    VAPP is an individual event in a recipient or contact and does not show community spread.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Pediatrics question

What is the answer to this Pediatrics question?

The best answer is B, Circulating vaccine-derived poliovirus. Vaccine-derived polioviruses arise when attenuated Sabin virus replicates for a long time and reverts.

Why is "Immunodeficiency-associated vaccine-derived poliovirus" not the answer?

This type arises from prolonged excretion by an immunodeficient individual, with no chain of community transmission.

Why is "Wild poliovirus type 1 infection" not the answer?

Isolates here are Sabin-derived, not wild virus.

Why is "Vaccine-associated paralytic poliomyelitis" not the answer?

VAPP is an individual event in a recipient or contact and does not show community spread.

What concept does this question test?

It tests Immunisation: circulating vaccine-derived poliovirus in Pediatrics. When linked isolates show person-to-person spread in a community with low immunity, they are classed as circulating VDPV and can cause outbreaks. VAPP is sporadic and affects a vaccine recipient or close contact without community spread.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Immunisation: circulating vaccine-derived poliovirus?

Memorise milestones and the vaccine schedule as tables and revise them often. Then use the flashcards and the other Pediatrics questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.