Systemwide Coordination for Timely Post-Exposure Prophylaxis in a Measles Outbreak

Session Description: In early 2025, a widespread measles outbreak in Texas revealed critical gaps in post-exposure prophylaxis (PEP) readiness, prompting a coordinated, systemwide response. Our acute care hospital led a large-scale, multi-site PEP initiative addressing high-risk exposures across inpatient units, ambulatory clinics, emergency centers, and affiliated academic practices.

Central to this effort was activation of our AMBUS (mobile medical unit), which served as the primary platform for administering MMR vaccines and immunoglobulin (IG). Over five months, the AMBUS enabled rapid delivery of prophylaxis to exposed patients, families, and community contacts. To expand access, after-hours PEP was also provided via the Emergency Centers and Urgent Cares, ensuring treatment within the narrow post-exposure window.

Exposures spanned multiple points of care, including the emergency department, inpatient units, sister clinics within our system, and a large academic faculty practice. An entire inpatient tower housing newborns and immunocompromised patients required urgent exposure assessment and containment. Many exposures were identified only after patient discharge or delayed diagnosis, complicating contact tracing and follow-up.

A dedicated four-person team contacted exposed individuals to evaluate immunization status, contraindications (e.g., immunosuppression, pregnancy), and PEP eligibility. Employee Health coordinated evaluation and treatment of exposed staff. Immunization record retrieval was labor-intensive, involving state registries, health department data, and electronic health records from multiple systems.

Behavioral challenges, such as vaccine refusal, public health mistrust, and loss to follow-up, impeded some efforts. Nevertheless, dozens of PEP doses were administered across the system, and no secondary transmission occurred among those receiving timely prophylaxis.

This response underscores the critical role of mobile health assets, centralized coordination, and flexible care delivery in managing large-scale measles exposures. As vaccine-preventable outbreaks grow in both frequency and complexity, healthcare systems must prepare to scale exposure management and PEP delivery while addressing the human factors that often complicate public health response.

Gillian Blackwell

Clinical Educator - Infection Prevention and Control, Employee Health, and Wound Care and Ostomy Services, UMC Health System

Gillian Blackwell, MPH, BSN, RN, CIC joined the UMC Health System team as an Infection Preventionist in January 2025. Prior to this role, she worked for seven years as the Public Health Region 1 Healthcare-Associated Infections (HAI) Epidemiologist for the Texas Department of State Health Services. She achieved her Bachelor of Science in Nursing (BSN) from Lubbock Christian University in 2016, earned her Certification in Infection Control (CIC) in 2017, and completed her Master of Public Health (MPH) at Texas Tech University Health Sciences Center in 2020. During her tenure with DSHS, Gillian played a key role in the Region 1 Epidemiology Team’s response to Hurricane Harvey and served as the primary infection control expert for the Texas Panhandle during the COVID-19 pandemic, as well as numerous outbreaks related to multidrug-resistant organisms. Her professional interests include emergency preparedness and disaster response, forensic nursing, and improving health literacy in the community.

Jennifer Clary

Director Infection Prevention and Control, Employee Health, Wound Care and Ostomy Services, UMC Healthsystem

Jennifer began her nursing career in 2003 with an Associates Degree in Nursing in telemetry and intermediate critical care and then private practice cardiology care. Subsequent practice experience includes perioperative care, postanesthesia care, and infection prevention / employee health. She started in Infection prevention and Employee health in 2011 and obtained her Certification in Infection Control and Epidemiology in 2013. She completed her Bachelors in Nursing in 2020. She obtained her Masters in Nursing with a specialization in Infection Control and Epidemiology in 2024. She is blessed to be a part of an amazing team at UMC and facilitates Infection Prevention and Employee Health with a team of Infection Preventionists, Employee Health nurses and wound care and ostomy nurses. She currently serves on the Board for the Texas Society of Infection Control and Prevention and assists with education development and delivery.

Aaron Woodall

Chief, Infection Prevention and Control, Department of Veterans Affairs

Aaron A. Woodall is an infection preventionist with nearly two decades of global experience. His career began in military combat medicine and public health efforts across Eastern Afghanistan, Europe, Middle East and Africa. His expertise spans many diverse healthcare environments.

Trent MacAllister

Infection Preventionist, Washington State Department of Health

Trent MacAllister, MPH, MS, CIC, is an Infection Preventionist at the Washington State Department of Health within the Healthcare-Associated Infections and Antimicrobial Resistance Section. In this role, Trent conducts Infection Control and Response (ICAR) consultations with healthcare facilities throughout the state. He has also provided outbreak investigation and response support to acute care, long-term care, ambulatory care, residential treatment, and behavioral health facilities. Trent worked as an infection preventionist in an acute care hospital before transitioning to his current role in public health. Trent is the Association for Professionals in Infection Control and Epidemiology (APIC) 2026 Annual Conference Committee (ACC) Chair. In his free time, Trent enjoys mountain biking, hiking, hanging out with his dogs at the lake, and traveling the world with his wife.