Immunisation: measles vaccine given before 9 months: 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: measles vaccine given before 9 months

Sample item

During a measles outbreak in a district, a 7-month-old infant is given a measles-containing vaccine dose. What is the correct approach to this infant's routine schedule?

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

The answer and the reasoning

C. Give the routine doses at 9 months and 16 to 24 months as well, as the early dose is not counted

In a measles outbreak a dose may be given from 6 months, but maternal antibody can neutralise the vaccine virus at this age, so the early dose is treated as an extra dose. The infant still needs the scheduled doses starting at 9 completed months. Repeat doses of live measles vaccine are safe.

Option by option

  • A. Consider the series complete because a dose has been given

    Maternal antibody can blunt the response before 9 months, so one early dose cannot be counted as a complete series.

  • B. Give only the second dose at 16 to 24 months

    Counting the early dose as dose one would leave the child with possibly one effective dose only.

  • C. Give the routine doses at 9 months and 16 to 24 months as well, as the early dose is not counted (correct)

    Correct. The early dose is additional and the routine schedule must still be completed.

  • D. Withhold all further measles-containing vaccine as a repeat dose is unsafe

    Extra doses of measles vaccine carry no added risk and are not withheld.

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, Give the routine doses at 9 months and 16 to 24 months as well, as the early dose is not counted. In a measles outbreak a dose may be given from 6 months, but maternal antibody can neutralise the vaccine virus at this age, so the early dose is treated as an extra dose.

Why is "Consider the series complete because a dose has been given" not the answer?

Maternal antibody can blunt the response before 9 months, so one early dose cannot be counted as a complete series.

Why is "Give only the second dose at 16 to 24 months" not the answer?

Counting the early dose as dose one would leave the child with possibly one effective dose only.

Why is "Withhold all further measles-containing vaccine as a repeat dose is u…" not the answer?

Extra doses of measles vaccine carry no added risk and are not withheld.

What concept does this question test?

It tests Immunisation: measles vaccine given before 9 months in Pediatrics. The infant still needs the scheduled doses starting at 9 completed months. Repeat doses of live measles vaccine are safe.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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: measles vaccine given before 9 months?

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.