What is Long COVID, and why is it so hard to treat?

Long COVID — clinically known as post-acute sequelae of SARS-CoV-2, or PASC — describes a wide range of symptoms that persist for weeks, months or years after a COVID-19 infection. Estimates suggest it affects between 6.6% and 10.3% of people who have had COVID-19, with the US Centers for Disease Control reporting that 8.7% of adults who had COVID still had active Long COVID symptoms as of mid-2024.

Symptoms vary widely but commonly include brain fog, fatigue, breathlessness, headache, dizziness, joint pain, sleep disturbance and sensory changes. What makes Long COVID particularly difficult to treat is that many of these symptoms don't have a clear structural cause — standard investigations often come back normal, leaving patients without answers and clinicians without a clear treatment path.

Increasingly, researchers believe that autonomic nervous system dysfunction — where the body's involuntary control systems become stuck in a state of chronic activation — is a central driver of Long COVID symptom burden. This is where the SGB comes in.

Why SGB? The nervous system connection

The Stellate Ganglion is a cluster of sympathetic nerve tissue in the neck that plays a key role in regulating the body's fight-or-flight response. An SGB involves injecting a local anaesthetic around this ganglion under image guidance — a safe, outpatient procedure that temporarily interrupts overactive sympathetic signalling.

SGB has been used for decades to treat pain and circulatory conditions. More recently it has attracted significant research interest for trauma and PTSD, where dysregulated sympathetic activity is similarly implicated. The logic for Long COVID follows a similar pathway: if persistent viral-induced nervous system dysregulation is driving symptoms, resetting sympathetic tone may offer meaningful relief.

What does the research show?

The evidence base is still developing, but the early findings across multiple independent studies are consistently encouraging.

Key findings at a glance

• A 2025 systematic review of seven studies found all reported symptomatic improvement following SGB, with response rates ranging from 55% to 100% across studies. (PMC, 2025)
• The most robust improvements — reported by more than 80% of patients — were seen in cough, breathlessness, headache, joint pain and sensory disturbances. (PMC, 2025)
• A retrospective cohort study of 52 patients at three sites in Boston found that most reported improvement in Long COVID symptoms after SGB, with brain fog, fatigue, dizziness and headache among the most commonly improved. (Chiang et al., Cureus, 2025)
• A separate cohort study found that 86% of patients experienced a reduction in Long COVID symptoms following SGB. (Pearson et al., Cureus, 2023)
• A 2025 prospective pilot study found SGB also reduced symptoms of SARS-CoV-2-induced ME/CFS — a condition that shares significant overlap with Long COVID — providing further support for the autonomic mechanism. (Taylor & Francis, 2025)

It is important to note that all studies to date are observational or retrospective in design — randomised controlled trials are underway but not yet completed. The evidence is promising but not yet definitive, and SGB is not currently established as a standard treatment for Long COVID.

Who might benefit?

Based on current research, SGB may be most relevant for people with Long COVID whose symptoms have an autonomic or nervous system character — particularly those experiencing:

• Persistent fatigue disproportionate to activity
• Brain fog, poor concentration or memory difficulties
• Dizziness, racing heart or orthostatic symptoms (feeling faint when standing)
• Persistent headache, joint pain or sensory changes
• Sleep disturbance, anxiety or heightened stress response
• Symptoms that have not adequately responded to other treatments

Individual suitability is assessed case by case. SGB is considered as a complementary option alongside — not a replacement for — other medical management and rehabilitation approaches.

What to do next

If you are living with Long COVID and feel your symptoms may have an autonomic component, SGB is worth exploring with a specialist.

The Stella Centre provides detailed clinical information, an online symptom assessment, and access to experienced interventional clinicians at Monash House Private Hospital in Melbourne and other smaller facilities in Sydney.

For clinicians: we welcome referrals for patients with Long COVID-related autonomic dysfunction. Please contact us referrers@stelacentre.com.au

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‍References

1. Stellate Ganglion Block in the Treatment of Long COVID: A Systematic Review. PMC / PubMed Central, 2025. pmc.ncbi.nlm.nih.gov/articles/PMC13076556/

2. Chiang MC et al. Stellate Ganglion Block for the Management of Long COVID Symptoms: A Retrospective Cohort Study. Cureus, July 2025. pubmed.ncbi.nlm.nih.gov/40861640/

3. Pearson L et al. Stellate Ganglion Block Relieves Long COVID-19 Symptoms in 86% of Patients: A Retrospective Cohort Study. Cureus, 2023. pubmed.ncbi.nlm.nih.gov/37711269/

4. Duricka D, Liu L. Reduction of Long COVID symptoms after stellate ganglion block: A retrospective chart review study. Autonomic Neuroscience, 2024. autonomicneuroscience.com

5. Stellate Ganglion Block reduces symptoms of SARS-CoV-2-induced ME/CFS: A prospective cohort pilot study. Taylor & Francis Online, published February 2025. tandfonline.com

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