When Lyme vs Long COVID Feels Impossible to Tell Apart

“Is this Lyme… or long COVID?”

Patients ask me this with a mix of fear and exhaustion. They describe the same constellation of symptoms — the brain fog that makes conversations feel slippery, the dizziness that hits out of nowhere, the heart that races as if the body is in danger, the fatigue that wipes out entire days.

Some became ill after COVID. Some after a tick bite. Many never saw a defining moment at all.

And that’s the challenge: the Lyme vs long COVID overlap is so significant that patients often find themselves dismissed, bounced between specialists, or told contradictory stories about their own illness.

Many describe feeling trapped between identities — not knowing whether Lyme, long COVID, or post-COVID symptoms explain the sudden unraveling of their health.

What the Research Shows About This Overlap

The patterns are not imagined.
They are documented.

The study Long-term neurologic outcomes of COVID-19 by Xu, Xie & Al-Aly demonstrated significantly higher rates of memory problems, slowed thinking, and difficulty concentrating in long COVID — symptoms identical to what I see in many Lyme patients.

And in my own published research, we compared individuals with a history of Lyme disease to those who later contracted COVID-19 or received the COVID-19 vaccine. The overall symptom burden did not significantly worsen after infection or vaccination, but about one in five who contracted COVID-19 went on to report long COVID.

That finding alone shows how intertwined Lyme vs long COVID can be.
— Cameron & McWhinney, Antibiotics, 2023

Where the Symptoms Converge

Brain Fog That Steals Sharpness

Patients from both groups describe the same cognitive struggle: the conversation that slips away, the tasks that suddenly feel too complicated, the words that disappear mid-sentence. Some call it “post-COVID brain fog,” others describe it as part of their Lyme journey — but the lived experience is eerily similar.

A Nervous System That Misfires

Dysautonomia ties Lyme vs long COVID together more than almost anything else.
Dizziness, heart palpitations, faintness, temperature swings — symptoms that mimic anxiety but aren’t driven by emotion. They arise from the autonomic nervous system losing its stability.

Fatigue That Feels Like a Crash, Not Tiredness

Both conditions produce a unique kind of exhaustion: the sudden collapse after a small effort, the days-long setback, the “wired but tired” state. Patients learn to fear exertion because even minor activity can push the system into shutdown.

Pain That Takes Many Forms

Headaches, nerve pain, muscle aches — Lyme may migrate while long COVID pain often stays fixed, but both can disrupt daily life with striking similarity.

The Pattern Most Doctors Miss: Cycling Symptoms

One of the strongest diagnostic clues in Lyme vs long COVID is the waxing and waning of symptoms.

Patients describe days where they feel nearly normal, followed by sudden crashes of dizziness, exhaustion, or cognitive fog. This fluctuation is often misread as stress or recovery — when in reality, it’s a defining feature of both illnesses.

In each condition, symptom cycling is not a sign of imagination or instability.
It is a hallmark of the underlying biology.

Why the Lyme vs Long COVID Confusion Happens

Most doctors are trained to look for illnesses that follow consistent, predictable patterns. Lyme and long COVID rarely do. Instead, their symptoms rise and fall, move from one system to another, and evolve over months or even years. Patients might have a normal exam one week and feel incapacitated the next. Their labs may look reassuring, even when their day-to-day life is anything but.

Because these illnesses don’t behave the way clinicians expect, many patients end up hearing explanations that never quite fit. They’re told they’re anxious. They’re told it’s simply “post-viral.” They’re told it can’t be Lyme without a rash, or long COVID if their original infection was mild. None of these assumptions match the lived reality of what patients are experiencing.

And so they land in a kind of diagnostic limbo — sick enough to lose pieces of their life, but not “sick enough” in ways the medical system easily recognizes. The overlap between Lyme vs long COVID becomes the blind spot where many patients disappear.

Patients Deserve a Better Way to Understand Lyme vs Long COVID

Both Lyme disease and long COVID — including persistent post-COVID symptoms — are post-infectious neuroinflammatory illnesses. Both can disrupt brain function, autonomic regulation, immune balance, and energy systems.

Patients shouldn’t have to choose the “right” label to receive care.They need clinicians who recognize the shared patterns and are willing to look deeper than a single test result.

If You’re Trying to Understand Your Own Overlap

You’re not alone. I hear from people every day who feel caught between Lyme vs long COVID, uncertain which path their illness followed — or whether it followed both.

Your symptoms make sense. The overlap is real. And there are answers.

Are you trying to understand your own Lyme vs long COVID symptoms?

Share your experience — your story may help someone else find clarity.

Resources

1. CDC. Long COVID Basics
2. Pubmed. Long-term neurologic outcomes of COVID-19
3. Dr. Daniel Cameron: Lyme Science Blog. Lyme, Long COVID, or Both? Making Sense of Persistent Symptoms
4. Dr. Daniel Cameron: Lyme Science Blog. Is it Long COVID or Lyme disease?