Hospital infection control: HIV post-exposure prophylaxis: practice question

A Microbiology 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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Microbiology · Hospital infection control: HIV post-exposure prophylaxis

Sample item

A resident doctor has a deep needle-stick injury from a patient with known HIV infection. Post-exposure prophylaxis is planned. What is the recommended timing and duration?

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

The answer and the reasoning

B. Start as early as possible, ideally within 2 hours and no later than 72 hours, and continue for 28 days

HIV post-exposure prophylaxis is most effective when started promptly, ideally within 2 hours and no later than 72 hours, using a combination of three antiretroviral drugs for 28 days. The wound is washed with soap and water, and baseline and follow-up HIV testing and counselling are done. Prophylaxis after the 72-hour window is not recommended.

Option by option

  • A. Give a single dose of zidovudine within 24 hours

    A single dose of one drug is inadequate; combination therapy for 28 days is required.

  • B. Start as early as possible, ideally within 2 hours and no later than 72 hours, and continue for 28 days (correct)

    Correct. Early three-drug therapy for 28 days is the recommended course.

  • C. Wait for the 6-week test result and then start for 3 months

    Waiting for 6-week test results would waste the window in which prophylaxis is effective.

  • D. Start within 7 days and continue for 7 days

    A 7-day course is too short, and starting after 72 hours is not recommended.

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 Microbiology question

What is the answer to this Microbiology question?

The best answer is B, Start as early as possible, ideally within 2 hours and no later than 72 hours, and continue for 28 days. HIV post-exposure prophylaxis is most effective when started promptly, ideally within 2 hours and no later than 72 hours, using a combination of three antiretroviral drugs for 28 days.

Why is "Give a single dose of zidovudine within 24 hours" not the answer?

A single dose of one drug is inadequate; combination therapy for 28 days is required.

Why is "Wait for the 6-week test result and then start for 3 months" not the answer?

Waiting for 6-week test results would waste the window in which prophylaxis is effective.

Why is "Start within 7 days and continue for 7 days" not the answer?

A 7-day course is too short, and starting after 72 hours is not recommended.

What concept does this question test?

It tests Hospital infection control: HIV post-exposure prophylaxis in Microbiology. The wound is washed with soap and water, and baseline and follow-up HIV testing and counselling are done. Prophylaxis after the 72-hour window is not recommended.

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 Hospital infection control: HIV post-exposure prophylaxis?

Make a one-line identity card for each organism: shape and stain, defining test, toxin, disease and drug. Then use the flashcards and the other Microbiology 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.