Immunisation: 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 · Immunisation

Sample item

Which vaccine is damaged by freezing and must be protected from it?

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

The answer and the reasoning

B. Hepatitis B vaccine

Adsorbed vaccines such as hepatitis B, DPT, DT, TT, Hib and pneumococcal conjugate lose potency when frozen because the aluminium adjuvant clumps. The shake test is used to check them. OPV, BCG (freeze-dried) and measles tolerate freezing.

Option by option

  • A. BCG vaccine

    BCG is freeze-dried and is damaged by heat and light, not freezing.

  • B. Hepatitis B vaccine (correct)

    Correct. Freezing destroys the adjuvant-antigen complex irreversibly.

  • C. Measles vaccine

    Measles vaccine can be stored frozen but must be protected from light.

  • D. Oral polio vaccine

    OPV is heat sensitive but can be stored frozen.

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.

More PSM questions

Questions about this PSM question

What is the answer to this PSM question?

The best answer is B, Hepatitis B vaccine. Adsorbed vaccines such as hepatitis B, DPT, DT, TT, Hib and pneumococcal conjugate lose potency when frozen because the aluminium adjuvant clumps.

Why is "BCG vaccine" not the answer?

BCG is freeze-dried and is damaged by heat and light, not freezing.

Why is "Measles vaccine" not the answer?

Measles vaccine can be stored frozen but must be protected from light.

Why is "Oral polio vaccine" not the answer?

OPV is heat sensitive but can be stored frozen.

What concept does this question test?

It tests Immunisation in PSM. The shake test is used to check them. OPV, BCG (freeze-dried) and measles tolerate freezing.

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?

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.