VZV Prophylaxis on Ibrutinib — RACP Adult Medicine MCQ
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Correct answer: E — Aciclovir 400 mg BD prophylaxis
Patients on ibrutinib (BTK inhibitor) for CLL have a significantly increased risk of herpes zoster reactivation due to impaired T-cell and NK-cell function. Aciclovir or valaciclovir prophylaxis is recommended for the duration of ibrutinib therapy and for 6–12 months after cessation. Shingrix (recombinant non-live vaccine) can also be administered but may have reduced immunogenicity in patients on active BTK inhibitor therapy. If VZV develops despite prophylaxis, therapeutic-dose antivirals should be commenced. Live varicella vaccine is CONTRAINDICATED in immunosuppressed patients.
Reference: eTG – 2025 – Haematology; ASCO – 2024 – Infection Prevention in CLL on BTKi