Hyperbaric Oxygen Therapy for Long COVID
Based on the most recent and highest quality evidence, hyperbaric oxygen therapy (HBOT) should NOT be routinely recommended for long COVID, as a 2025 randomized placebo-controlled trial found no significant benefit over placebo for symptoms, functional scores, or cognitive performance. 1
Critical Evidence Analysis
The strongest available evidence comes from a 2025 double-blind, randomized, placebo-controlled trial that directly contradicts earlier promising reports:
- 101 patients were randomized to four treatment groups including true HBOT (100% oxygen at 2.5 atmospheres), lower oxygen doses, and placebo (room air at normal pressure) 1
- No significant differences emerged between any groups in subjective symptoms, quality of life scores (Visual Analogue Scale, EQ-5D-5L, C19-YRSm), 6-minute walking test, or five neurocognitive tests 1
- The placebo group showed similar improvements to the treatment groups, suggesting earlier positive reports likely reflected placebo effects rather than true therapeutic benefit 1
- At 3-month follow-up, no lasting effects were demonstrated in any treatment arm 1
Earlier Contradictory Studies
While earlier studies suggested benefit, they had critical methodological limitations:
- A 2021 case series of 10 patients showed improvements in fatigue and cognition, but lacked a control group and blinding, making placebo effects impossible to exclude 2
- A 2022 single case report demonstrated improvements in a 55-year-old man, but individual case reports cannot establish treatment efficacy 3
- A 2024 systematic review identified mostly uncontrolled studies and small trials, acknowledging that "further rigorous large-scale RCTs are required" 4
Clinical Implications
The 2025 randomized trial represents the highest quality evidence available and should guide clinical decision-making:
- HBOT is expensive, time-consuming (typically 10-60 sessions), and resource-intensive 1
- No subgroups of long COVID patients responded better to any oxygen treatment regimen 1
- The highly variable response across all groups, including placebo, reflects the natural fluctuation of long COVID symptoms rather than treatment effect 1
Important Caveats
- Long COVID remains a significant health burden affecting approximately 50 million individuals worldwide with no proven effective treatments 5
- The absence of evidence for HBOT does not mean other supportive interventions are ineffective—symptom-directed management remains appropriate
- Patients reporting improvement after HBOT in clinical practice may be experiencing placebo effects, natural disease fluctuation, or regression to the mean 1
Current Guideline Position
No major respiratory or critical care guidelines recommend HBOT for long COVID. The available COVID-19 management guidelines from the European Respiratory Society and Surviving Sepsis Campaign address only acute COVID-19 respiratory failure, not post-acute sequelae 6. HBOT guidelines address only carbon monoxide poisoning, not viral syndromes 6.