Clinical trial Recruiting at 3 sites Interventional Ages 18 and up

Hi-OxSR to treat post-COVID cognitive problems

Official title: RECLAIM: Recovering From COVID-19 Lingering Symptoms Adaptive Integrative Medicine Trial - Effect of Hi-OxSR for the Treatment of Post COVID Condition (RECLAIM-HiOxSR)

Run by University Health Network, Toronto · NCT06928506 · Data updated 2026-11-12

This trial will test whether using the Hi-OxSR breathing device can help adults with long COVID who have ongoing cognitive problems and fatigue.

Quick facts

Study typeInterventional
Ages18 Years and up
SexAll
Enrollment120 (estimated)
SponsorUniversity Health Network, Toronto
Academic / other
Locations3 sites (Edmonton, Alberta and 2 other locations)
StatusRecruiting
StartedAugust 1, 2025
Main results expectedFebruary 2028
Study endsApril 2029
Registry record updatedOctober 22, 2026
Trial IDNCT06928506 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Adults aged 18 or older with confirmed or presumed COVID at least three months earlier who continue to have self-reported cognitive dysfunction for at least two months despite standard care would be typical candidates.

Probably not a fit

People without ongoing cognitive symptoms, those whose COVID occurred less than three months ago, or those with contraindications to rebreathing or supplemental oxygen are unlikely to benefit.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This phase 2 sub-protocol within the RECLAIM platform tests Hi-OxSR and Hi-Ox devices in adults with post-COVID cognitive dysfunction to determine optimal dose, duration, and safety. The trial builds on an open-label pilot where twice-daily CO2 rebreathing with Hi-OxSR for 14 days produced improvements on cognitive tests, brain fog, and fatigue scores. Participants will be assigned to different device settings and usage lengths (varying oxygen concentration and with or without CO2 rebreathing) to identify the most effective and safe approach. The study is conducted at sites in Toronto, Edmonton, and Sherbrooke.

Why it matters

Potential benefit: If successful, it could provide a non-drug breathing therapy that reduces brain fog and fatigue in people with long COVID.

How similar studies have gone: A small open-label pilot using twice-daily Hi-OxSR for 14 days reported significant improvements in cognitive tests, brain fog, and fatigue, but larger randomized data are not yet available.

Who can join: the full rules

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Age ≥18 years;
2. Positive COVID-19 test by nasopharyngeal swab RT-PCR (reverse transcription polymerase chain reaction) test, antibody or antigen tests at least 3 months prior to randomization; OR Presumed COVID-19 assessed by the site investigator (no positive COVID-19 test) with acute illness after October 15, 2019.
3. Patients should be treated with standard of care therapies (as discussed in the study manual) for at least 4 weeks prior to entry into trial.
4. Lingering COVID-19 symptoms beyond 3 months from onset of acute COVID and symptoms have lasted at least 2 months. The onset of COVID is considered the earliest of two dates: the date of positive test or the date of first symptoms;
5. Lingering symptoms from COVID-19 present at the time of randomization. "Lingering symptoms of Long COVID" must include self-reported cognitive dysfunction symptoms.
6. Female patients of childbearing potential (as assessed by the overseeing Investigator) who are sexually active must agree to practice true abstinence or use effective methods of contraception while on study treatment. Effective methods of contraception must be discussed and approved by the overseeing Investigator.
7. Must be able to provide informed consent and both willing and able to comply with study requirements.
8. Oxygen saturation on room air ≥92% at screening measured by pulse oximeter.

Exclusion Criteria:

1. Patients who had mechanical ventilation or extracorporeal membrane oxygen (ECMO) for COVID-19;
2. Current end-organ failure, organ transplantation, or current hospitalization in acute care hospital;
3. Contraindications to all of the study interventions;
4. Co-enrolment in another interventional trial (co-enrolment in an observational study is permitted);
5. Currently pregnant or breastfeeding.
6. Known physician diagnosis of cognitive dysfunction prior to COVID infection
7. Use of an investigational drug/device or other interventions within 30 days of screening
8. Use of home oxygen (O2) at baseline
9. History of pulmonary hypertension
10. Interstitial pulmonary fibrosis
11. Moderate to severe chronic obstructive pulmonary disease (COPD)
12. History of narcolepsy
13. Presence of a condition or abnormality that in the opinion of the investigator would compromise the safety of the participant or the quality of the data.

Where it's running

  • Kaye Edmonton Clinic
    Edmonton, Alberta, Canada
    Recruiting
  • University Health Network
    Toronto, Ontario, Canada
    Recruiting
  • Centre Hospitalier Universitaire de Sherbrooke
    Sherbrooke, Quebec, Canada
    Recruiting

Study contacts

  • Principal investigator: Angela M Cheung, MD, PhD — University Health Network, Toronto
  • Study coordinator: suzanne Cohen
  • Email: reclaim@uhn.ca
  • Phone: 1-866-673-2524

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

  • Hyperbaric oxygen therapy for Long COVID cognitive symptoms

    This study will test whether hyperbaric oxygen therapy can improve lingering cognitive symptoms like brain fog and memory problems in adults who had COVID-19.

    Recruiting University Health Network, Toronto · Toronto, Ontario · NCT06452095

  • Combination therapy for Long COVID symptoms using valacyclovir, celecoxib, and Paxlovid

    This study tests whether a three-drug combination can reduce Long COVID symptoms in adults compared with a placebo.

    Recruiting Phase 2 Icahn School of Medicine at Mount Sinai · New York, New York · NCT07597902

  • Mitochondrial oxygen use in blood, muscle, and skin of people with long COVID

    Researchers will test whether mitochondria use oxygen differently in blood cells, muscle, and skin of people with long COVID compared with people who fully recovered after COVID-19.

    Recruiting Universitair Ziekenhuis Brussel · Jette, Brussels Capital · NCT07134673

  • Imaging brain inflammation in people with long COVID symptoms

    This study is testing if a brain scan can show signs of inflammation in people aged 18 to 70 who have neurological symptoms after COVID-19, and whether a treatment called IVIg can help them feel better.

    Recruiting Phase 1 National Institutes of Health Clinical Center (CC) · Bethesda, Maryland · NCT06920628

  • Rehabilitation program to reduce fatigue after COVID-19

    This study is testing a new rehabilitation program called COVIDEx to see if it can help people with Long COVID feel less tired compared to standard care.

    Recruiting London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's · London, Ontario · NCT06156176

  • Mind-body intervention for people with Long COVID

    This study is testing a mind-body program to see if it can help people with Long COVID feel better and improve their daily activities.

    Recruiting Beth Israel Deaconess Medical Center · Boston, Massachusetts · NCT06045338

How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.