Long COVID Treatment Trials: What the Latest Research Shows

Long COVID has emerged as one of the most complex post-infectious syndromes in modern medicine, affecting an estimated 10–30% of people who contract SARS-CoV-2. As of 2024, more than 200 clinical trials are actively investigating treatments, and early results are beginning to reshape how clinicians approach this condition. This article summarizes the most clinically relevant findings for patients with Long COVID and associated dysautonomia.

The Challenge of Treating a Heterogeneous Syndrome

One of the central difficulties in Long COVID research is that the syndrome is not a single disease. Patients present with vastly different symptom profiles — some dominated by post-exertional malaise and cognitive dysfunction, others by cardiovascular dysregulation (POTS), and still others by mast cell activation, immune dysregulation, or viral persistence. This heterogeneity means that no single treatment is likely to work for all patients, and trials that enroll broad populations may dilute signals that would be significant in specific subgroups.

The NIH RECOVER initiative has been the largest coordinated effort to understand and treat Long COVID, enrolling over 17,000 participants across dozens of sites. While RECOVER has been criticized for moving slowly and prioritizing observational data over interventional trials, its 2023–2024 interventional phase has begun producing actionable results.

Antiviral Approaches: Paxlovid Extended Courses

The hypothesis that Long COVID is driven in part by persistent viral reservoirs has led to trials of extended antiviral therapy. Paxlovid (nirmatrelvir/ritonavir), approved for acute COVID-19, has been studied in Long COVID patients who did not receive it during acute illness or who received it too late.

The RECOVER-VITAL trial enrolled approximately 900 Long COVID patients and randomized them to 15-day or 25-day courses of Paxlovid versus placebo. Preliminary results presented in late 2023 showed modest but statistically significant improvement in fatigue and cognitive symptoms in the 15-day arm, with diminishing returns in the 25-day arm. Patients with detectable viral RNA in nasal swabs or stool showed greater benefit, supporting the viral persistence hypothesis in a subset of patients.

Importantly, patients with POTS or autonomic dysfunction were not specifically stratified in RECOVER-VITAL, making it difficult to draw conclusions for this subgroup. Anecdotal reports from patients with Long COVID POTS suggest mixed responses — some experience significant improvement, others report worsening of dysautonomia symptoms during the ritonavir component due to drug interactions with medications like propranolol and ivabradine.

Low-Dose Naltrexone: Emerging Evidence

Low-dose naltrexone (LDN, 1.5–4.5 mg/day) has been used off-label for ME/CFS, fibromyalgia, and Crohn's disease for over a decade. Its proposed mechanisms — microglial modulation, endorphin upregulation, and anti-inflammatory effects — are directly relevant to Long COVID's neuroinflammatory component.

A 2023 Norwegian randomized controlled trial of LDN in Long COVID (n=86) found significant improvements in fatigue, pain, and cognitive function at 12 weeks compared to placebo. The effect size was moderate (Cohen's d ≈ 0.5), and the treatment was well-tolerated with minimal side effects. A larger UK trial (STIMULATE-ICP) included LDN as one arm and reported similar findings.

For patients with Long COVID POTS, LDN may be particularly relevant because it appears to reduce neuroinflammation in the hypothalamus and brainstem — regions critical for autonomic regulation. Several autonomic specialists have begun incorporating LDN into Long COVID POTS protocols, typically starting at 0.5 mg and titrating slowly over 8–12 weeks.

IVIG and Immunomodulation

Intravenous immunoglobulin (IVIG) has shown promise in a subset of Long COVID patients, particularly those with evidence of autoantibodies against autonomic receptors (anti-beta-adrenergic, anti-muscarinic). A 2023 German case series of 10 Long COVID POTS patients treated with IVIG showed dramatic improvement in 7 of 10, with normalization of heart rate response on tilt table testing in 4 patients.

The LIINC-IVIG trial at UCSF is currently enrolling patients with Long COVID and evidence of autoimmune dysautonomia to receive either IVIG or placebo. Results are expected in 2025. In the meantime, some immunologists are offering IVIG off-label to Long COVID patients with documented autoantibodies and severe functional impairment.

Plasmapheresis (therapeutic plasma exchange) has also been studied in small series, with a German group reporting significant improvement in Long COVID patients with high autoantibody titers. This approach is more invasive and expensive than IVIG, but may be appropriate for patients who do not respond to IVIG.

BC007 and Autoantibody-Targeted Therapies

BC007 is an aptamer (short DNA molecule) that neutralizes autoantibodies against G-protein-coupled receptors, including the beta-adrenergic and muscarinic receptors implicated in Long COVID POTS. A Phase 2 trial in Germany showed significant improvement in Long COVID patients with confirmed autoantibodies, with effects lasting up to 6 months after a single infusion.

This approach is not yet available outside clinical trials, but represents one of the most mechanistically targeted therapies under investigation. Patients interested in this approach can inquire about trial eligibility at the Berlin Charité or through the Long COVID Alliance trial registry.

[Stellate Ganglion Block](/glossary#term-stellate-ganglion-block)

The stellate ganglion block (SGB) is an anesthetic injection into the stellate ganglion — a sympathetic nerve cluster in the neck — that has been used for decades to treat hot flashes, PTSD, and complex regional pain syndrome. In Long COVID, the hypothesis is that SGB may reset an overactivated sympathetic nervous system.

A 2023 case series of 12 Long COVID patients with POTS who received SGB reported significant improvement in heart rate variability, orthostatic tolerance, and fatigue in 8 of 12 patients. Effects lasted 3–6 months. A randomized controlled trial is underway at Stanford. SGB is available at many pain clinics and is generally safe when performed by an experienced practitioner, though it is not yet a standard-of-care treatment for Long COVID.

Pacing and Rehabilitation Trials

The STIMULATE-ICP trial in the UK compared four approaches: usual care, antihistamines (loratadine + famotidine), LDN, and a pacing/rehabilitation program. The pacing arm showed significant improvement in fatigue and quality of life, with the key finding being that graded exercise therapy (GET) was harmful in Long COVID patients with PEM — a finding consistent with ME/CFS research and now reflected in updated UK NICE guidelines.

The pacing program used in STIMULATE-ICP was heart rate-guided, with patients instructed to keep their heart rate below their anaerobic threshold (typically calculated as 220 minus age, multiplied by 0.6 for Long COVID patients). This approach, sometimes called "heart rate-based pacing" or "energy envelope theory," is now the recommended rehabilitation approach for Long COVID patients with PEM.

What This Means for Patients

The emerging picture from 2023–2024 trials is that Long COVID treatment should be stratified by phenotype:

No single treatment works for all phenotypes, and many patients have overlapping presentations. The most important step is working with a clinician who understands Long COVID's heterogeneity and can help identify which phenotype(s) apply to your case.

ChatDys resources: Track your symptoms and treatment responses in the Health Tracker. Upload your lab results including autoantibody panels to Biomarkers. If you are considering LDN, review our dedicated LDN for Long COVID article in the Long COVID filter.