Communicable diseases: hepatitis A epidemiological transition: 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: hepatitis A epidemiological transition

Sample item

Over two decades, a rapidly developing Indian city improves its piped water and sanitation. Subclinical hepatitis A infections in early childhood fall, yet doctors now see more symptomatic jaundice and occasional fulminant hepatitis in adolescents and adults. What best explains this?

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

The answer and the reasoning

B. More non-immune older persons, who develop symptomatic infection

Hepatitis A is usually silent in young children. With better sanitation, fewer children are infected early, so more adolescents and adults remain susceptible, and when infected they develop symptomatic and sometimes severe disease. This epidemiological transition is why vaccination is considered in such settings.

Option by option

  • A. Shift of transmission to the parenteral route

    Hepatitis A is spread by the faeco-oral route, and parenteral spread is not the mechanism.

  • B. More non-immune older persons, who develop symptomatic infection (correct)

    Correct. Later first exposure shifts infection to ages where it is more often symptomatic and severe.

  • C. Mutation of the virus to a more virulent strain

    Nothing in the stem suggests a change in viral virulence, and the pattern is explained by age at first infection.

  • D. Waning of vaccine-induced immunity in the population

    The stem does not describe widespread vaccination, and infection-induced immunity is lifelong.

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, More non-immune older persons, who develop symptomatic infection. Hepatitis A is usually silent in young children.

Why is "Shift of transmission to the parenteral route" not the answer?

Hepatitis A is spread by the faeco-oral route, and parenteral spread is not the mechanism.

Why is "Mutation of the virus to a more virulent strain" not the answer?

Nothing in the stem suggests a change in viral virulence, and the pattern is explained by age at first infection.

Why is "Waning of vaccine-induced immunity in the population" not the answer?

The stem does not describe widespread vaccination, and infection-induced immunity is lifelong.

What concept does this question test?

It tests Communicable diseases: hepatitis A epidemiological transition in PSM. With better sanitation, fewer children are infected early, so more adolescents and adults remain susceptible, and when infected they develop symptomatic and sometimes severe disease. This epidemiological transition is why vaccination is considered in such settings.

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 Communicable diseases: hepatitis A epidemiological transition?

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.