Trastuzumab Should Be Continued During Rabies Vaccination
Continue adjuvant trastuzumab without interruption when administering rabies vaccine to patients with HER2-positive breast cancer. There are no contraindications to receiving inactivated vaccines, including rabies vaccine, while on trastuzumab therapy.
Rationale for Continuation
Trastuzumab is a monoclonal antibody, not a cytotoxic chemotherapy agent, and does not cause the degree of immunosuppression that would contraindicate inactivated vaccines 1, 2.
Rabies vaccine is an inactivated (killed) vaccine, which poses no risk of causing infection even in immunocompromised patients and can be safely administered during biologic therapy 1.
Interrupting trastuzumab therapy carries significant oncologic risk as adjuvant trastuzumab for 1 year reduces the 3-year risk of recurrence by approximately 50% and improves overall survival by one-third in HER2-positive breast cancer 3, 4.
Key Treatment Principles
The standard duration of adjuvant trastuzumab is 52 weeks (1 year) and should be completed without interruption unless cardiac toxicity develops 5.
Cardiac monitoring is the primary safety concern with trastuzumab, not immunosuppression—baseline and periodic LVEF assessments are required, with discontinuation only if LVEF falls below 50-55% or symptomatic heart failure develops 5, 2.
Unlike concurrent anthracycline administration (which is contraindicated due to cardiotoxicity), there is no evidence that inactivated vaccines interact adversely with trastuzumab 5, 4.
Common Pitfalls to Avoid
Do not confuse trastuzumab with cytotoxic chemotherapy—while chemotherapy may cause significant immunosuppression requiring vaccine timing considerations, trastuzumab is a targeted biologic agent with a completely different mechanism and safety profile 1, 2.
Do not delay or interrupt trastuzumab for vaccine administration—any interruption in the 52-week adjuvant course compromises the proven survival benefit without any evidence-based justification 3, 6.
Do not withhold rabies post-exposure prophylaxis if indicated—rabies is universally fatal once symptomatic, and the inactivated vaccine poses no risk to patients receiving trastuzumab 1.
Clinical Implementation
Administer the rabies vaccine series (pre- or post-exposure) on schedule while continuing trastuzumab at the standard dosing of either weekly (2 mg/kg after 4 mg/kg loading) or every 3 weeks (6 mg/kg after 8 mg/kg loading) 5.
Continue routine cardiac monitoring per standard trastuzumab protocols—the vaccine does not alter cardiac risk or monitoring requirements 2, 4.
Document the vaccine administration but no additional laboratory monitoring or trastuzumab dose adjustments are needed 1.