Communicable diseases: typhoid conjugate vaccine: practice question

A PSM 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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PSM · Communicable diseases: typhoid conjugate vaccine

Sample item

A reason typhoid conjugate vaccine is preferred over the plain Vi polysaccharide vaccine is that it:

ACan be given to infants from 6 months and gives longer lasting T-cell dependent immunityBNeeds boosters every yearCIs a live oral vaccineDIs effective only in adults

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

The answer and the reasoning

A. Can be given to infants from 6 months and gives longer lasting T-cell dependent immunity

Typhoid conjugate vaccine links Vi polysaccharide to a carrier protein, making the response T-cell dependent so that it works in young children and gives longer protection. Vi polysaccharide vaccine is poorly immunogenic below 2 years.

Option by option

A. Can be given to infants from 6 months and gives longer lasting T-cell dependent immunity (correct)
Correct. Conjugation extends use to infants and improves durability.
B. Needs boosters every year
It does not need yearly boosters.
C. Is a live oral vaccine
Conjugate vaccine is injectable and not live oral.
D. Is effective only in adults
It is intended for children and adults.

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.

Questions about this PSM question

What is the answer to this PSM question?

The best answer is A, Can be given to infants from 6 months and gives longer lasting T-cell dependent immunity. Typhoid conjugate vaccine links Vi polysaccharide to a carrier protein, making the response T-cell dependent so that it works in young children and gives longer protection.

Why is "Needs boosters every year" not the answer?

It does not need yearly boosters.

Why is "Is a live oral vaccine" not the answer?

Conjugate vaccine is injectable and not live oral.

Why is "Is effective only in adults" not the answer?

It is intended for children and adults.

What concept does this question test?

It tests Communicable diseases: typhoid conjugate vaccine in PSM. Vi polysaccharide vaccine is poorly immunogenic below 2 years.

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 Communicable diseases: typhoid conjugate vaccine?

Practise biostatistics with small calculations until sensitivity, predictive values and risk measures are automatic. Then use the flashcards and the other PSM 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.