Background: The Swedish Cancer Institute (SCI) is committed to holistic care and recognizes immunizations are an essential component to quality outcomes. In 2022 the SCI was selected to participate in the Specialty Societies Advancing Adult Immunization (SSAAI) project supported by the Centers for Disease Control and Prevention (CDC) with a goal of incorporating the CDC Standards for Adult Immunization Practice into medical oncology clinical care. The CDC Standards for Adult Immunization Practice are assess, recommend, administer or refer, and document. Recognizing immunization status is not routinely assessed, this quality initiative aimed to increase assessment of immunization status in medical oncology across 7 network clinics on 4 campuses to above 50 % by the end of 2023. Methods: All team members completed the ASCO Quality Training Program. The Plan Do Study Act (PDSA) framework was selected. Assessment was defined as having completed the Immunization Activity Record within the Epic Medical Record system, which includes reconciliation with the Washington state immunization registry. Data was initially abstracted manually to determine the baseline assessment rate until an automated method was developed. A Fishbone diagram determined the top barrier was the lack of awareness about this functionality and lack of training around the task. A workflow diagram and standard operating procedure were implemented. Clinic staff were trained on the new workflow when rooming patients. A small pilot with one clinic of solid tumor medical oncology clinics was completed. Patients included were on active treatment and seen face to face within the clinic. The standardized process and tools were refined, and problem areas addressed. The work was then expanded to all seven of the SCI network medical oncology clinics including hematology as the final PDSA cycle using the same training, process and tools. Results: The Epic Immunization Activity Record completion rate went from less than 1% of solid tumor patients with an active systemic treatment plan to 61% in the pilot project. After two additional PDSA cycles to refine the steps and target problem areas, the rate improved to 67% over a 3-month period. The PDSA cycle was expanded to bring the refined process to all 7 network clinics with a baseline assessment rate of 6% which increased to 45% after interventions within a 3-month period and concluding the 2023 year. Conclusions: Developing tools and implementing a new workflow for immunization assessment yielded a significant improvement in assessment rates thereby setting a foundation of assessment utilizing the CDC Standards for Immunization Practice. The use of concrete written tools improves the sustainability of the changes. Additional tools and refinement of existing tools will be studied to improve the current rate and sustain the gains. Reference: Standards for Adult Immunization Practices | CDC.