Virology: hepatitis B reactivation: 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 · Virology: hepatitis B reactivation

Sample item

A 55-year-old man with diffuse large B-cell lymphoma is about to start rituximab-containing chemotherapy. Serology shows HBsAg negative, total anti-HBc positive and anti-HBs negative. What is the most appropriate management?

AMake no intervention and repeat HBsAg after 5 yearsBStart entecavir or tenofovir before chemotherapy and continue it for at least 12 months after completionCGive hepatitis B vaccine and proceed without antiviral therapyDGive hepatitis B immunoglobulin alone as a single dose

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

The answer and the reasoning

B. Start entecavir or tenofovir before chemotherapy and continue it for at least 12 months after completion

Isolated anti-HBc positivity usually represents resolved infection in which covalently closed circular DNA persists in hepatocytes. B-cell depletion with rituximab carries a high risk of reactivation with severe hepatitis, so prophylaxis with a high-barrier nucleoside analogue is recommended and continued for at least 12 months after treatment. Monitoring alone is used in lower-risk settings.

Option by option

A. Make no intervention and repeat HBsAg after 5 years
Waiting leaves the patient exposed to reactivation, which usually occurs during or soon after chemotherapy.
B. Start entecavir or tenofovir before chemotherapy and continue it for at least 12 months after completion (correct)
Antiviral prophylaxis prevents reactivation from latent viral DNA during profound B-cell depletion.
C. Give hepatitis B vaccine and proceed without antiviral therapy
Vaccination cannot produce protection in time and does not suppress existing latent virus.
D. Give hepatitis B immunoglobulin alone as a single dose
Immunoglobulin gives short-lived passive cover and does not suppress intrahepatic viral DNA.

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 Microbiology question

What is the answer to this Microbiology question?

The best answer is B, Start entecavir or tenofovir before chemotherapy and continue it for at least 12 months after completion. Isolated anti-HBc positivity usually represents resolved infection in which covalently closed circular DNA persists in hepatocytes.

Why is "Make no intervention and repeat HBsAg after 5 years" not the answer?

Waiting leaves the patient exposed to reactivation, which usually occurs during or soon after chemotherapy.

Why is "Give hepatitis B vaccine and proceed without antiviral therapy" not the answer?

Vaccination cannot produce protection in time and does not suppress existing latent virus.

Why is "Give hepatitis B immunoglobulin alone as a single dose" not the answer?

Immunoglobulin gives short-lived passive cover and does not suppress intrahepatic viral DNA.

What concept does this question test?

It tests Virology: hepatitis B reactivation in Microbiology. B-cell depletion with rituximab carries a high risk of reactivation with severe hepatitis, so prophylaxis with a high-barrier nucleoside analogue is recommended and continued for at least 12 months after treatment. Monitoring alone is used in lower-risk 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 Virology: hepatitis B reactivation?

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.