RecruitingNCT07134673

Mitochondrial Function in Peripheral Blood Mononuclear Cells, Muscle, and Skin of Long COVID Patients

Mitochondrial Oxygen Consumption and Substrate Utilisation In Vitro in Peripheral Blood Mononuclear Cells, and In Vivo on Muscle and Skin in Long COVID Patients and Convalescent Individuals: A Case-Control and Diagnostic Accuracy Study

Sponsor

Universitair Ziekenhuis Brussel

Enrollment

54 participants

Start Date

Jan 21, 2026

Study Type

OBSERVATIONAL

Conditions

Long COVID

Summary

Mitochondria are structures inside cells that are responsible for producing energy from nutrients through a series of steps, using oxygen. To have an idea of how well the mitochondria can produce energy, we can measure how much oxygen they use. The goal of this study is to: 1. To compare the oxygen use between people with long COVID and people who completely recovered after COVID-19, using three techniques that measure the oxygen use in blood cells, on the skin and in the muscle 2. To test how similar these three techniques are in measuring the oxygen used in the three different tissues Participants will: * Complete surveys, * Wear an activity tracker (7 days), * Undergo several non-invasive tests, and * Donate a blood sample The study will take place in UZ Brussel hospital and will take 2 study visits, approximately 7 days apart.

Eligibility

Min Age: 18 Years

Inclusion Criteria10

Individuals with long COVID:
Long COVID diagnosis, based on the WHO definition;
Presence of long COVID symptoms for a minimum of 6 months.
History of confirmed or documented SARS-CoV-2 infection.
Adult (≥18 years of age).
Post-COVID-19 Functional Status Scale grade 2-4, while they had a grade 0 before the SARS-CoV-2 infection.
History of confirmed or documented SARS-CoV-2 infection.
Complete recovery after the SARS-CoV-2 infection, no history of long COVID based on the WHO definition;
Post-COVID-19 Functional Status Scale \[2\] grade 0 both before the infection and currently.
Adult (≥18 years of age).

Exclusion Criteria13

Pre-existing chronic diseases potentially affecting the functional status scale.
Treatment with metabolism altering drugs.
> 10 standard units of alcohol (10 grams of alcohol/glass) per week.
Unable to understand oral and written instructions in Dutch, French or English.
Allergies to medical adhesive bandages.
Porphyria and other skin conditions aggravated by sunlight.
Convalescent individuals
Pre-existing chronic non-communicable diseases (e.g. hypertension, chronic respiratory diseases, diabetes).
Treatment with metabolism altering drugs.
> 10 standard units of alcohol (10 grams of alcohol/glass) per week.
Unable to understand oral and written instructions in Dutch, French or English.
Allergies to medical adhesive bandages.
Porphyria and other skin conditions aggravated by sunlight.