Preventive medicine: 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.

Try it

PSM · Preventive medicine

Sample item

A community has very high immunisation coverage for several vaccines. Which disease would gain little community-level benefit from herd immunity?

ATetanusBMeaslesCDiphtheriaDPoliomyelitis

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

The answer and the reasoning

A. Tetanus

Herd immunity works by reducing the chance that a susceptible person meets an infectious person, so it requires person-to-person transmission. Tetanus spores come from the environment and are not passed between people, so unimmunised individuals gain no indirect protection.

Option by option

A. Tetanus (correct)
Correct. Infection comes from environmental spores, so only personal immunity protects.
B. Measles
Measles spreads person to person, so high coverage lowers exposure of the susceptible.
C. Diphtheria
Diphtheria spreads between people and herd effects reduce circulation of the organism.
D. Poliomyelitis
Poliovirus spreads between people, so population immunity limits its transmission.

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, Tetanus. Herd immunity works by reducing the chance that a susceptible person meets an infectious person, so it requires person-to-person transmission.

Why is "Measles" not the answer?

Measles spreads person to person, so high coverage lowers exposure of the susceptible.

Why is "Diphtheria" not the answer?

Diphtheria spreads between people and herd effects reduce circulation of the organism.

Why is "Poliomyelitis" not the answer?

Poliovirus spreads between people, so population immunity limits its transmission.

What concept does this question test?

It tests Preventive medicine in PSM. Tetanus spores come from the environment and are not passed between people, so unimmunised individuals gain no indirect protection.

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 Preventive medicine?

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.