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Why Do Lungs Stay Inflamed After COVID-19?
For many patients who have recovered from acute COVID-19 infection, the lungs do not simply return to normal. Persistent lung inflammation—characterized by ongoing shortness of breath, reduced exercise tolerance, chest tightness, and a lingering cough—affects a significant proportion of long COVID patients. Understanding why this happens is the first step toward effective treatment.
At St. George Hospital (Klinik St. Georg) in Bad Aibling, Germany, we have treated hundreds of patients with post-COVID respiratory complications. Dr. Julian Douwes, Chief Medical Officer, notes: “The lungs are among the most commonly affected organs in long COVID. What we see is not simply residual infection, but an ongoing inflammatory and microvascular process that requires targeted intervention.”
The Mechanisms Behind Persistent Lung Inflammation
Several interconnected biological processes drive post-COVID lung inflammation:
- Endothelial dysfunction: SARS-CoV-2 damages the endothelium—the inner lining of blood vessels in the lungs. This damage persists long after the virus is cleared, leading to impaired gas exchange and ongoing inflammation.
- Microclot formation: Research by Dr. Beate Jaeger and others has identified persistent microclots in the blood of long COVID patients. These fibrin-amyloid deposits impair microcirculation in the pulmonary vasculature, starving lung tissue of oxygen and fueling inflammation. This represents an important research direction in understanding post-COVID pathology.
- Immune dysregulation: The immune system can remain in a state of chronic activation, with elevated inflammatory cytokines (IL-6, TNF-alpha, interferon-gamma) perpetuating tissue damage even in the absence of active viral replication.
- Fibrotic changes: In some patients, the inflammatory response triggers the deposition of scar tissue (fibrosis) in the lung parenchyma, which can permanently reduce lung capacity if not addressed early.
- Mast cell activation: Emerging evidence suggests that mast cell activation syndrome (MCAS) may contribute to ongoing pulmonary symptoms, including bronchospasm and mucus production.
The Fibrosis Risk: Why Early Treatment Matters
Pulmonary fibrosis is perhaps the most concerning long-term consequence of post-COVID lung inflammation. Once fibrotic tissue replaces functional lung parenchyma, the damage is largely irreversible. Early intervention to reduce inflammation and promote tissue repair is therefore critical.
Risk factors for developing post-COVID pulmonary fibrosis include:
- Severe acute COVID-19 requiring hospitalization or oxygen support
- Prolonged symptoms beyond 12 weeks
- Persistent ground-glass opacities on CT imaging
- Elevated inflammatory markers (CRP, ferritin, D-dimer)
- Pre-existing lung conditions
- Age over 60
Patients presenting with these risk factors should seek comprehensive evaluation at a facility experienced in post-COVID care. Our post-COVID treatment program addresses the full spectrum of respiratory complications.
Diagnostic Evaluation of Post-COVID Lung Inflammation
Accurate diagnosis is essential before beginning treatment. At St. George Hospital, our diagnostic protocol for post-COVID pulmonary patients includes:
Imaging
- High-resolution CT (HRCT): Identifies ground-glass opacities, interstitial changes, fibrotic bands, and bronchiectasis
- Chest X-ray: Baseline assessment and follow-up monitoring
Pulmonary Function Testing
- Spirometry: Measures restrictive and obstructive patterns
- Diffusion capacity (DLCO): Assesses gas exchange efficiency—often significantly reduced in post-COVID patients
- 6-minute walk test: Evaluates functional exercise capacity and desaturation
Blood Work
- Inflammatory markers: CRP, IL-6, ferritin
- Coagulation panel: D-dimer, fibrinogen (to assess microclot burden)
- Autoimmune screening
- Oxidative stress markers
Treatment Approaches for Post-COVID Lung Inflammation
Ozone Therapy for Pulmonary Recovery
Medical ozone therapy is one of the most effective interventions we use for post-COVID lung inflammation. Ozone (O3) is a potent modulator of the immune system and a powerful enhancer of tissue oxygenation.
How ozone helps post-COVID lungs:
- Improved oxygenation: Ozone increases the release of oxygen from hemoglobin to tissues (via the 2,3-DPG pathway), directly addressing the oxygen deficit caused by damaged lung vasculature.
- Anti-inflammatory effects: Controlled oxidative stress induced by ozone activates the Nrf2 antioxidant pathway, which downregulates pro-inflammatory cytokines.
- Immune modulation: Ozone helps rebalance an overactive immune response, reducing the chronic inflammation that drives lung damage.
- Improved microcirculation: Ozone enhances red blood cell flexibility and reduces blood viscosity, improving flow through damaged pulmonary capillaries.
At St. George Hospital, we administer ozone via major autohemotherapy (MAH): the patient’s blood is drawn, mixed with a precise ozone-oxygen mixture, and reinfused. Sessions are typically administered 2–3 times per week over a 2–4 week treatment course.
Interval Hypoxia-Hyperoxia Training (IHHT)
IHHT, also known as altitude training therapy, is a non-invasive approach that stimulates the body’s natural regenerative mechanisms at the mitochondrial level.
How IHHT works:
- The patient breathes alternating intervals of low-oxygen (hypoxic) and high-oxygen (hyperoxic) air through a mask while resting comfortably.
- Hypoxic intervals trigger a process called mitophagy—the selective destruction of damaged mitochondria.
- Hyperoxic intervals stimulate the production of new, healthy mitochondria (mitochondrial biogenesis).
For post-COVID lung patients, IHHT offers several benefits:
- Improved cellular energy production in damaged lung tissue
- Enhanced oxygen utilization efficiency
- Reduced exercise-induced desaturation
- Improved exercise tolerance over a 10–15 session course
Research has demonstrated that IHHT can improve mitochondrial function and exercise capacity in patients with chronic respiratory conditions (Serebrovska et al., Frontiers in Physiology, 2021).
Apheresis for Microclot Removal
For patients with evidence of persistent microclots and impaired microcirculation, H.E.L.P. apheresis can directly filter pathological proteins and microclots from the blood. This is particularly relevant for patients whose lung inflammation is driven by endothelial dysfunction and impaired pulmonary microcirculation.
Intravenous Therapies
- High-dose vitamin C: Potent antioxidant and anti-inflammatory, supports immune rebalancing
- Glutathione: The body’s master antioxidant, often depleted in post-COVID patients
- NAD+ infusions: Support mitochondrial repair in damaged lung tissue. Learn more about our NAD+ IV therapy program.
- Alpha-lipoic acid: Antioxidant that crosses the blood-brain barrier and supports both pulmonary and neurological recovery
Pulmonary Rehabilitation
Physical rehabilitation is an essential complement to the biological therapies listed above:
- Guided breathing exercises to improve lung capacity
- Progressive exercise training with oxygen saturation monitoring
- Respiratory physiotherapy
- Stress reduction and autonomic nervous system regulation
Treatment Timeline and Expected Outcomes
Most patients at St. George Hospital undergo a 2–4 week inpatient treatment program for post-COVID lung inflammation. Expected outcomes include:
- Week 1: Reduction in inflammatory markers, initial improvement in energy levels
- Week 2–3: Measurable improvement in pulmonary function (spirometry, DLCO), reduced shortness of breath
- Week 4+: Continued improvement in exercise tolerance, ongoing reduction in fibrotic risk
- 3–6 months post-treatment: Many patients report sustained improvement, particularly when home maintenance protocols are followed
It is important to note that individual outcomes vary based on the severity of initial lung damage, duration of symptoms, and overall health status.
Frequently Asked Questions
How long does post-COVID lung inflammation last without treatment?
Without targeted intervention, post-COVID lung inflammation can persist for months or even years. Some patients experience gradual improvement over 6–12 months, while others develop chronic respiratory impairment. The risk of progression to pulmonary fibrosis makes early, proactive treatment advisable, particularly for patients with persistent symptoms beyond 12 weeks.
Is ozone therapy safe for damaged lungs?
Yes, when administered by experienced physicians. It is important to understand that medical ozone therapy does not involve inhaling ozone gas. The treatment is delivered intravenously through major autohemotherapy, which has an excellent safety profile. At St. George Hospital, we have administered thousands of ozone treatments with a very low rate of adverse events. Ozone therapy is contraindicated in patients with G6PD deficiency, which is screened for before treatment.
Can post-COVID lung fibrosis be reversed?
Early fibrotic changes (ground-glass opacities, early interstitial thickening) may be partially reversible with aggressive anti-inflammatory treatment. Established fibrosis (dense scarring) is generally irreversible, which is why early intervention is so important. Our approach focuses on halting the progression of fibrosis and maximizing the function of remaining healthy lung tissue.
How does IHHT differ from supplemental oxygen therapy?
Supplemental oxygen passively provides more oxygen to breathe. IHHT, by contrast, actively trains the body’s cells to use oxygen more efficiently by stimulating mitochondrial renewal. The hypoxic intervals trigger the body to produce new, healthier mitochondria, while the hyperoxic intervals support their growth. The result is improved cellular energy production—a fundamentally different and more durable benefit than simply breathing more oxygen.
Begin Your Recovery
If you are experiencing persistent shortness of breath, reduced exercise tolerance, or chest tightness months after a COVID-19 infection, early evaluation and treatment can make a significant difference. Our post-COVID treatment program at St. George Hospital combines advanced diagnostics with targeted biological therapies to address the root causes of ongoing lung inflammation.
Contact our international patient team to schedule a consultation.
Phone: +49 (0)8061 398-0
Email: info@clinicum-stgeorg.de
Location: Rosenheimer Str. 6-8, 83043 Bad Aibling, Germany
Disclaimer: The treatments described in this article are offered as part of an integrative medical approach. Individual outcomes vary. Post-COVID treatment protocols at St. George Hospital are based on clinical experience and emerging research. Patients should discuss all treatment options with their healthcare providers.
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