Lyme Disease or Long COVID? How to Tell the Difference

Persistent symptoms after infection
Why Lyme disease and Long COVID can look alike
How careful evaluation guides diagnosis and treatment

Recovering from Lyme disease only to develop COVID-19 months or years later can create a confusing situation. Some patients find that fatigue, brain fog, joint pain, dizziness, and exercise intolerance return after COVID-19, leaving them wondering whether they have Long COVID, a recurrence of Lyme disease symptoms, or both.

In my own peer-reviewed study of 889 patients with a history of Lyme disease, many individuals reported worsening symptoms after COVID-19 infection or vaccination, highlighting the complex relationship between these post-infectious illnesses.

This scenario is becoming increasingly common. Many patients discover that Lyme disease or Long COVID can feel remarkably similar, creating diagnostic uncertainty for both patients and clinicians.

Patients often wonder whether they have COVID and Lyme disease, Long COVID, persistent Lyme disease, or another post-infectious syndrome. The overlap can be especially confusing when fatigue, brain fog, pain, dizziness, autonomic symptoms, and post-exertional malaise occur together.

Is it Lyme disease or Long COVID?

Lyme disease and Long COVID share several overlapping symptoms, making diagnosis and treatment challenging in some cases. These similarities often lead to confusion among patients and healthcare providers, especially when clear diagnostic markers are lacking. Both illnesses may also fluctuate over time, with periods of improvement followed by relapse.

Both Lyme disease and Long COVID can leave patients with the same frustrating issues:

1. Brain fog that won’t lift — Losing words mid-sentence, forgetting why you walked into a room, or struggling with once-automatic tasks. Learn more about brain fog in Lyme disease.
2. Exhaustion that sleep doesn’t fix — Sleeping 10 hours yet waking up drained.
3. Your heart acting up — Racing when you stand, skipped beats, palpitations, or unexplained tachycardia.
4. Pain that travels — Aching muscles and joints that migrate from one location to another.
5. Post-exertional malaise (PEM) — Even light physical or mental activity may trigger a delayed worsening of fatigue, pain, cognitive symptoms, or dizziness. Although PEM is widely recognized in Long COVID and ME/CFS, many patients with persistent Lyme disease also report similar post-exertional symptom flares.

Lyme disease vs. Long COVID: similarities and differences

Feature	Lyme disease	Long COVID
Cause	Borrelia burgdorferi infection	Post-SARS-CoV-2 illness
Fatigue	Common	Common
Brain fog	Common	Common
Joint and muscle pain	Common	Common
Post-exertional malaise	Can occur	Common
Dysautonomia / POTS	Can occur	Can occur
Antibiotics	May benefit patients with active Lyme disease or tick-borne coinfections	Not a treatment for Long COVID itself
Diagnostic testing	Clinical evaluation supported by laboratory testing	Primarily clinical diagnosis

Why do Lyme disease and Long COVID feel so similar?

Although Lyme disease is caused by a bacterial infection and Long COVID follows SARS-CoV-2 infection, both illnesses appear capable of disrupting multiple body systems. Ongoing immune activation, nervous system dysfunction, inflammation, and impaired cellular energy production may all contribute to persistent symptoms.

1. Persistent immune activation. Both illnesses may trigger prolonged immune responses that continue long after the initial infection.
2. Immune dysregulation. The immune system may remain overactive or fail to return to its normal baseline, contributing to fatigue, pain, and cognitive dysfunction.
3. Neurologic involvement. Both conditions may affect the brain and peripheral nervous system, leading to memory problems, headaches, sleep disturbance, mood changes, dizziness, and neuropathic symptoms.
4. Mitochondrial dysfunction. Emerging research suggests impaired mitochondrial function may contribute to reduced cellular energy production, fatigue, exercise intolerance, and slower recovery.
5. Autonomic nervous system dysfunction. Many patients develop dysautonomia, including orthostatic intolerance, POTS, temperature dysregulation, gastrointestinal dysmotility, abnormal sweating, exercise intolerance, and heart rate instability. Learn more about autonomic dysfunction in Lyme disease.

The important difference: Lyme disease begins as a bacterial infection. Patients with evidence of active Lyme disease or tick-borne coinfections may benefit from antimicrobial treatment, while others with persistent symptoms may require broader evaluation and supportive care. Long COVID is generally managed as a post-viral condition affecting immune, neurologic, autonomic, vascular, and metabolic pathways.

Can Lyme disease and Long COVID be confused?

Yes. Lyme disease and Long COVID frequently resemble one another because both may produce fatigue, brain fog, chronic pain, dizziness, autonomic dysfunction, and post-exertional symptom worsening.

A 2024 machine-learning study demonstrated that although Long COVID and chronic Lyme disease have substantial clinical overlap, they appear to exhibit different cytokine signatures. The authors specifically noted that fatigue, post-exertional malaise, and brain fog overlap significantly between Long COVID, chronic Lyme disease, and ME/CFS.

Importantly, the study also reported post-exertional malaise in both patient groups. While PEM was more common among the Long COVID cohort, it was also observed in patients with chronic Lyme disease, supporting what many clinicians caring for Lyme patients observe in practice.

Rather than assuming PEM automatically indicates Long COVID, clinicians should interpret it within the broader clinical picture, including tick exposure, timing of illness, COVID history, coinfections, autonomic dysfunction, neurologic findings, and treatment response.

Lyme Disease vs. Long COVID Treatment

Treatment differs because Lyme disease and Long COVID arise from different infections and involve different underlying mechanisms. Lyme disease begins as a bacterial infection, whereas Long COVID is considered a post-viral syndrome following SARS-CoV-2 infection.

Patients with evidence of active Lyme disease or tick-borne coinfections may benefit from antimicrobial treatment. Others with persistent symptoms after appropriate treatment may require a broader approach that addresses inflammation, autonomic dysfunction, sleep, pain, cognitive symptoms, rehabilitation, and other contributing factors.

Long COVID does not respond to antibiotics as a treatment for the post-viral illness itself. Instead, management often focuses on symptom-directed care, pacing to reduce post-exertional symptom flares, autonomic rehabilitation, sleep optimization, physical and cognitive rehabilitation when tolerated, and treatment of specific organ-system complications.

Treatment responses may provide useful clinical clues.

If Lyme disease is contributing, patients may:

1. Improve with antibiotics when active infection remains present.
2. Respond to treatment for tick-borne coinfections such as Babesia.
3. Experience migratory musculoskeletal pain, neurologic symptoms, or relapsing illness after tick exposure.
4. Require evaluation for persistent inflammation, immune dysfunction, or coinfections.

If Long COVID is contributing, patients may:

1. Develop symptoms following confirmed or suspected COVID-19 infection.
2. Experience prominent post-exertional malaise requiring careful pacing.
3. Require treatment for dysautonomia, POTS, breathing abnormalities, chest discomfort, or exercise intolerance.
4. Benefit from therapies aimed at supporting nervous system recovery and improving daily function.

Recovery rarely follows a simple path. Some patients appear to have overlapping mechanisms, making individualized treatment especially important.

When patients face both conditions

Some patients who recovered from Lyme disease later developed persistent symptoms after COVID-19, while others experienced recurrence or worsening of previous Lyme-related symptoms. These observations have led researchers to investigate whether COVID-associated immune changes may unmask previously controlled illness, amplify chronic inflammation, or worsen autonomic dysfunction.

This creates several clinical challenges:

1. Determining whether symptoms reflect Long COVID, Lyme disease, both conditions, or another post-infectious syndrome.
2. Deciding whether antimicrobial therapy, immune-directed treatment, autonomic rehabilitation, or a combination is most appropriate.
3. Setting realistic expectations when multiple organ systems are involved.

Rather than asking whether symptoms are caused by Lyme disease or Long COVID, clinicians may achieve better results by identifying which biologic mechanisms are currently driving illness.

What I’ve seen in clinical practice

Over nearly four decades of treating Lyme disease, I have cared for several groups of patients whose experiences highlight the overlap between Lyme disease and Long COVID.

• Some patients with a history of Lyme disease later developed Long COVID, leaving them with symptoms that were difficult to distinguish from their earlier Lyme illness.
• Some patients experienced delays in Lyme disease diagnosis because their new fatigue, brain fog, dizziness, or post-exertional symptom flares were initially attributed to Long COVID. In several cases, treatment for Lyme disease was postponed while another explanation was pursued.
• Others reported that symptoms previously attributed to Lyme disease recurred or worsened after COVID-19 infection. Whether this reflects immune dysregulation, autonomic dysfunction, persistent inflammation, another mechanism, or a combination remains an active area of investigation.

These clinical observations reinforce the importance of keeping an open differential diagnosis. Patients with persistent symptoms after COVID-19 may have Long COVID, Lyme disease, both conditions, or another illness that deserves careful evaluation.

Managing Overlapping Symptoms

Patients and clinicians can often make progress by addressing common pathways shared by both illnesses while continuing to evaluate the underlying diagnosis.

1. Reduce ongoing inflammation when immune activation appears to contribute to symptoms.
2. Support mitochondrial function and cellular energy production when fatigue and exercise intolerance predominate.
3. Treat autonomic dysfunction, including POTS, orthostatic intolerance, gastrointestinal dysmotility, temperature dysregulation, sweating abnormalities, and heart-rate instability.
4. Address neurologic dysfunction including brain fog, headaches, neuropathic symptoms, sleep disturbance, and sensory sensitivity.
5. Evaluate for active infection or coinfections when the history, examination, laboratory findings, or treatment response suggests persistent tick-borne illness.

For more information about persistent symptoms after Lyme disease treatment, see Post-Treatment Lyme Disease Syndrome (PTLDS) and Persistent Lyme Disease Mechanisms.

Key Takeaways for Patients

1. Your symptoms are real and deserve careful evaluation.
2. Lyme disease and Long COVID share many symptoms, including fatigue, brain fog, autonomic dysfunction, chronic pain, and post-exertional malaise.
3. PEM is not exclusive to Long COVID and may also occur in patients with persistent Lyme disease.
4. Diagnosis often depends on careful clinical history, exposure risk, timing of symptoms, laboratory findings, and treatment response.
5. An individualized treatment plan is often more helpful than relying on a single diagnostic label.

For a comprehensive overview of the relationship between COVID-19 and Lyme disease — including my peer-reviewed study involving 889 patients — see Long COVID and Lyme Disease: What Patients Need to Know.

Frequently Asked Questions

Can Lyme disease cause symptoms similar to Long COVID?

Yes. Both illnesses commonly cause fatigue, brain fog, chronic pain, dizziness, autonomic dysfunction, sleep disturbance, and post-exertional malaise, making diagnosis challenging.

Can post-exertional malaise occur in Lyme disease?

Yes. Although post-exertional malaise is widely recognized in Long COVID and ME/CFS, many patients with persistent Lyme disease also report delayed worsening of fatigue, pain, dizziness, and cognitive symptoms following physical or mental exertion.

Can COVID make old Lyme symptoms return?

Some patients report recurrence or worsening of previous Lyme-related symptoms after COVID-19 infection. Although research continues, COVID-associated immune dysregulation may contribute to symptom recurrence in susceptible individuals.

Can you have Lyme disease and Long COVID at the same time?

Yes. Some individuals with a history of Lyme disease later develop Long COVID after SARS-CoV-2 infection, creating overlapping clinical features that require careful evaluation.

How can doctors tell the difference?

Diagnosis relies on clinical history, timing of illness, tick exposure, COVID history, laboratory testing when appropriate, neurologic and autonomic findings, and response to treatment. No single symptom reliably distinguishes one condition from the other.

What should I do if I have symptoms of both?

Seek evaluation from a clinician experienced in post-infectious illnesses who can consider Lyme disease, Long COVID, autonomic dysfunction, coinfections, and other causes of persistent symptoms while developing an individualized treatment plan.

Clinical Takeaway

Lyme disease and Long COVID have different causes, yet both can produce persistent fatigue, brain fog, chronic pain, dysautonomia, and post-exertional malaise. The overlap is substantial, making careful clinical evaluation essential.

Current evidence suggests that persistent symptoms may reflect different combinations of immune dysregulation, autonomic dysfunction, neuroinflammation, mitochondrial dysfunction, and — in some patients — ongoing tick-borne infection or coinfection.

Although Lyme disease and Long COVID share many symptoms, careful clinical evaluation remains essential because the underlying mechanisms — and the treatments that may help — can differ substantially.

Related Articles

Learn more about persistent Lyme disease, autonomic dysfunction, and recovery:

Lyme Disease Symptoms Guide
Recovery from Lyme Disease
POTS Similarities Seen in Long COVID and Lyme Disease
Neurologic Lyme Disease
Lyme Disease Fatigue

References

1. Cameron DJ. Consequences of Contracting COVID-19 or Taking the COVID-19 Vaccine for Individuals with a History of Lyme Disease. Antibiotics. 2023.
2. Patterson BK, Guevara-Coto J, Mora J, et al. Long COVID diagnostic with differentiation from chronic Lyme disease using machine learning and cytokine hubs. Scientific Reports. 2024;14:19743.
3. Steere AC, Strle F, Wormser GP, Hu LT, Branda JA, Hovius JWR, Li X, Mead PS. Lyme borreliosis. Nature Reviews Disease Primers. 2016;2:16090.
4. Roos KL. Neurologic Complications of Lyme Disease. Continuum (Minneap Minn). 2021;27(4):1040-1050.

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Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.

Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention