Abemaciclib and Yellow Fever Vaccine: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 10, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Yellow Fever Vaccine
Abemaciclib
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
Let's talk about this one carefully. Abemaciclib (Verzenio) is a cancer medicine that can weaken your immune system. The yellow fever vaccine is a live vaccine, meaning it contains a weakened form of the actual virus. In a healthy person, the immune system easily handles that weakened virus and builds protection.
But if your defenses are lowered by chemotherapy, that live virus can potentially cause a real infection, including serious problems like brain swelling (encephalitis). That is why these two should generally not be combined. Please don't make any changes on your own. Talk with your oncologist or pharmacist before any travel or vaccine, and they will help you plan safely.
Contraindicated combination. Abemaciclib (a CDK4/6 inhibitor) causes immunosuppression, and yellow fever vaccine is a live-attenuated viral vaccine.
- Direction/effect: Blunted immune response permits uncontrolled replication of the vaccine virus, risking vaccine-associated disease (encephalitis, viscerotropic disease).
- Mechanism: Pharmacodynamic, not PK; neither agent is metabolically dependent on the other.
- Evidence: Established; onset unspecified.
- Management: Avoid live vaccination and travel to endemic areas during immunosuppression. Live vaccines may be considered only in patients with disease remission, restored immunocompetence, and chemotherapy discontinued at least 3 months.
What happens
An increased risk of infection by the live vaccine
Interaction Deep Dive
Patients who are immunosuppressed should avoid both the yellow fever vaccine and travel to regions where yellow fever is endemic. Receiving the yellow fever vaccine carries a risk of encephalitis as well as other serious adverse events1. A live vaccine may be given to individuals with leukemia, lymphoma, or other malignancies provided their disease is in remission, their immunocompetence has been restored, and at least 3 months have passed since chemotherapy was stopped2.
Why it happens (mechanism)
Decreased immune response allows live vaccine to produce infection
How to manage this interaction
The main step here is avoidance. While you are on abemaciclib and your immune system is suppressed, the yellow fever vaccine should not be given, and travel to yellow fever endemic areas is not advised.
- Keep taking your abemaciclib exactly as prescribed. Do not change it on your own.
- Tell your oncologist and pharmacist about any upcoming travel well in advance so they can plan.
- Live vaccination may only be reconsidered by your care team once your disease is in remission, your immune function has recovered, and chemotherapy has been stopped for at least 3 months.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Abemaciclib and Yellow Fever Vaccine together?
Do not get the yellow fever vaccine or travel to endemic areas while on abemaciclib, because this live vaccine could cause a serious infection in a weakened immune system. Talk with your oncologist to plan travel safely. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abemaciclib and Yellow Fever Vaccine interaction?
It is rated contraindicated. These should generally not be used together.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Abemaciclib and Yellow Fever Vaccine interaction managed?
The main step here is avoidance. While you are on abemaciclib and your immune system is suppressed, the yellow fever vaccine should not be given, and travel to yellow fever endemic areas is not advised. Keep taking your abemaciclib exactly as prescribed. Do not change it on your own. Tell your oncologist and pharmacist about any upcoming travel well in advance so they can plan. Live vaccination ma… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "established". Well documented — supported by controlled studies or strong clinical data.
Questions for your pharmacist
- Does my dose of Abemaciclib or Yellow Fever Vaccine need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (2)
- Product Information: YF-VAX(R) subcutaneous injection, yellow fever vaccine subcutaneous injection. Sanofi Pasteur Inc (per FDA), Swiftwater, PA, 2016. DailyMed
- Centers for Disease Control and Prevention (CDC): Vaccines & Immunizations: altered immunocompetence. Centers for Disease Control and Prevention (CDC). Atlanta, GA. 2024.
Keep reading about Yellow Fever Vaccine
Keep reading about Abemaciclib
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