Immunisation: herd immunity and measles: 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: herd immunity and measles

Sample item

Measles has a basic reproduction number of 12 to 18. What level of population immunity is needed to interrupt transmission?

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

The answer and the reasoning

C. More than 95 percent

Herd immunity threshold is approximately 1 minus 1/R0, and for measles with R0 of 12 to 18 it exceeds 92 to 95 percent. This is why two doses and high coverage are needed.

Option by option

  • A. About 50 percent

    Fifty percent would suffice for a disease with R0 near 2.

  • B. About 70 percent

    Seventy percent is enough for diseases with R0 near 3.

  • C. More than 95 percent (correct)

    Correct. Over 95 percent coverage is required.

  • D. About 30 percent

    Thirty percent is far too low.

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 C, More than 95 percent. Herd immunity threshold is approximately 1 minus 1/R0, and for measles with R0 of 12 to 18 it exceeds 92 to 95 percent.

Why is "About 50 percent" not the answer?

Fifty percent would suffice for a disease with R0 near 2.

Why is "About 70 percent" not the answer?

Seventy percent is enough for diseases with R0 near 3.

Why is "About 30 percent" not the answer?

Thirty percent is far too low.

What concept does this question test?

It tests Immunisation: herd immunity and measles in Pediatrics. This is why two doses and high coverage are needed.

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: herd immunity and measles?

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.