The National Academies Forum on Microbial Threats and Forum on Neuroscience and Nervous System Disorders hosted a hybrid public workshop in June 2023 to explore opportunities to advance research and treatment of infection-associated chronic illnesses. The illnesses discussed in this workshop, including COVID-19, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), persistent or posttreatment Lyme disease syndrome (PTLDS), and multiple sclerosis (MS), share overlapping mechanisms and symptoms and have been inadequately researched. Recognizing these commonalities, speakers identified the need to advance research more comprehensively, translating to improved diagnostic and treatment options for patients across multiple conditions. Table of Contents Front Matter 1 Introduction 2 Overview of Infection-Associated Chronic Illnesses 3 Common Mechanistic Factors of Infection-Associated Chronic Illnesses 4 Potential Research Priorities and Opportunities in Diagnostics 5 Potential Research Priorities and Opportunities in Therapeutics 6 Advancing Research for Infection-Associated Chronic Illnesses 7 Considering Challenges and Opportunities in a Shared Research Agenda Appendix A: References Appendix B: Workshop Statement of Task Appendix C: Workshop Agenda