Chronic Infections and Inflammation in ME/CFS: An Observational Study (CHIIME)

CHIIME is a study of people who have myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). People who do not have this condition will also be enrolled. Volunteers will be observed and sampled over time to identify the long-terms biological drivers and impact of their condition. The overall goal is to understand the biological and physiological mechanisms that are driving this condition.

Study Overview

• Status: Recruiting
• Conditions: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Detailed Description

CHIIME is an observational, prospective study of individuals who have myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The overall objective of the study is to investigate the clinical characteristics and biological signatures of ME/CFS over time by performing deep clinical phenotyping with high-quality biospecimen collection and curation of individuals with and without the condition.

Enrolled volunteers will be seen at San Francisco General Hospital. Visits include a detailed interview, biospecimen collection, and various assessments. No personal identifiers are used for specimen bank samples.

• Study Type: Observational
• Enrollment (Estimated): 200

Contacts and Locations

• Study Contact: Name: Beatrice Program Manager; Phone Number: (415) 502-2449; Email: chiime@ucsf.edu
• Study Contact Backup: Name: Brent RN; Email: chiime@ucsf.edu

Study Locations

• United States
  • California
    • San Francisco, California, United States, 94110
      • Recruiting
      • Zuckerberg San Francisco General Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

The investigators will enroll individuals with a diagnosis of ME/CFS across a wide spectrum of age, race, gender, and disease severity and will also enroll a subset of people without ME/CFS or other infection associated chronic conditions (healthy control)

Description

Inclusion Criteria:

• Willing and able to provide written informed consent
• At least 18 years of age
• Either: (1) a reported diagnosis of ME/CFS or (2) no history of ME/CFS or other infection-associated chronic conditions (healthy control)

Exclusion Criteria:

• Self reported or documented chronic anemia with hemoglobin <9 g/dL
• Known HIV, hepatitis B, or hepatitis C infection
• Diagnosis of an infection-associated chronic condition other than ME/CFS or Long COVID (e.g. chronic Lyme disease, post-Ebola syndrome, etc.)
• Serious medical or psychiatric illness that, in the opinion of the site investigator, would interfere with the ability to adhere to study requirements or to give informed consent
• Active drug or alcohol use or dependence that, in the opinion of the PI, would interfere with adherence to study requirements or to give informed consent

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort
Non-COVID ME/CFS; Individuals who received a diagnosis of ME/CFS prior to the beginning of SARS-CoV-2 pandemic and whom SARS-CoV-2 was not expected to be the driver of ME/CFS
Post-COVID ME/CFS; Individuals who received a diagnosis of ME/CFS following the beginning of the SARS-CoV-2 pandemic and in who SARS-CoV-2 was expected to be the driver of ME/CFS
Healthy control; Individuals who have overlapping demographic characteristics (age, sex, race, and other factors determined by PI) with participants who have ME/CFS

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Participant Sex	The proportion of men and women participating in the baseline visit.	Baseline Visit
Participant Age	The median age of study participants at enrollment.	Baseline Visit
Participant race/ethnicity	The proportion of participants from each demographic group.	Baseline Visit

Collaborators and Investigators

• Sponsor: University of California, San Francisco
• Investigators: Principal Investigator: Michael J. Peluso, University of California, San Francisco

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2026
• Primary Completion (Estimated): September 1, 2030
• Study Completion (Estimated): September 1, 2030

Study Registration Dates

• First Submitted: November 10, 2025
• First Submitted That Met QC Criteria: November 10, 2025
• First Posted (Actual): November 12, 2025

Study Record Updates

• Last Update Posted (Actual): March 6, 2026
• Last Update Submitted That Met QC Criteria: March 4, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: chronic fatigue syndrome; ME/CFS; myalgic encephalomyelitis
• Additional Relevant MeSH Terms: Neuroinflammatory Diseases; Musculoskeletal Diseases; Nervous System Diseases; Muscular Diseases; Pathologic Processes; Encephalomyelitis; Neuromuscular Diseases; Chronic Disease; Disease Attributes; Pathological Conditions, Signs and Symptoms; Fatigue Syndrome, Chronic
• Other Study ID Numbers: 24-43260

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No