Can Lyme Disease Kill You? What the Evidence Shows

Deaths from Lyme disease are rare
Lyme carditis can be life-threatening
Early recognition of warning signs matters

Can Lyme disease kill you? In most cases, Lyme disease is not fatal, particularly when it is recognized and treated early. However, rare deaths have been documented, particularly when Lyme disease affects the heart.

Because death is so uncommon, there is no reliable single fatality percentage that applies to every person diagnosed with Lyme disease. The evidence instead shows that deaths directly attributed to Lyme disease are rare, while certain complications—especially Lyme carditis—can become life-threatening.

Lyme Disease Is Usually Not Fatal

In most cases, Lyme disease is not deadly, particularly when diagnosed and treated early.

Borrelia burgdorferi, the bacterium that causes Lyme disease in the United States, is treated with antibiotics such as doxycycline, amoxicillin, or cefuroxime, depending on the clinical presentation and individual patient.

However, untreated infection may spread and affect the heart, nervous system, or joints. Although uncommon, some complications can become dangerous.

What Is the Fatality Rate of Lyme Disease?

The fatality rate of Lyme disease is extremely low, but there is no reliable single percentage that applies to all diagnosed cases.

A U.S. review of death certificates from 1999 through 2003 found 114 records that listed Lyme disease as an underlying or contributing cause of death. After investigators reviewed the records, only one was consistent with clinical manifestations of Lyme disease. The authors concluded that Lyme disease is rare as a cause of death in the United States.

A separate CDC investigation examined 121,894 reported Lyme disease cases from selected high-incidence states. Among these patients, 702 died from all causes within one year of diagnosis. After review, only two deaths—0.002% of the total group—were classified as suspected Lyme carditis-associated deaths. This figure should not be interpreted as a universal Lyme disease fatality rate because it came from a specific surveillance population and included only suspected cardiac deaths identified through that investigation.

Earlier national surveillance data also found cardiac manifestations in about 1.1% of reported Lyme disease cases for which clinical information was available. Cardiac involvement is therefore uncommon, and fatal cardiac involvement is rarer still.

The important distinction is that rare does not mean impossible. Documented deaths have occurred, particularly when cardiac involvement was not recognized before a dangerous conduction abnormality or sudden cardiac death.

1. Lyme Carditis

Lyme disease may affect the heart’s electrical conduction system, causing Lyme carditis.

Inflammation involving the conduction pathways can lead to rhythm abnormalities, including varying degrees of atrioventricular heart block. Although symptomatic cardiac involvement is uncommon, severe conduction abnormalities can become life-threatening.

In 2013, the CDC reported three cases of sudden cardiac death associated with Lyme carditis. The patients were 26 to 38 years old and lived in states with a high incidence of Lyme disease. Postmortem examinations found evidence of Lyme carditis.

Symptoms that may occur with Lyme carditis include:

• Chest pain
• Shortness of breath
• Palpitations
• Lightheadedness
• Fainting

These symptoms require prompt medical evaluation. For additional case examples, see Can You Die From Lyme Disease? When Lyme Carditis Becomes Fatal.

2. Neurologic Lyme Disease

In some patients, Lyme disease affects the nervous system, leading to neurologic Lyme disease or neuroborreliosis.

Recognized neurologic manifestations can include meningitis, cranial neuropathy, radiculoneuritis, numbness, pain, and weakness. Other neurologic or cognitive symptoms may also require evaluation depending on the clinical presentation.

Severe neurologic illness can be clinically significant, but the clearest documented mechanism for rare sudden deaths directly associated with Lyme disease has been cardiac involvement rather than neurologic Lyme disease.

For a broader overview, see neurologic Lyme disease.

3. Babesia Co-infection

The ticks that transmit Lyme disease may also transmit Babesia, a parasite that infects red blood cells.

Babesiosis is a separate tick-borne infection rather than a complication caused by Lyme disease itself. This distinction matters when discussing the fatality rate of Lyme disease.

Severe babesiosis can cause hemolytic anemia, thrombocytopenia, hemodynamic instability, acute respiratory distress, kidney or liver dysfunction, and other serious complications. Fatal cases can occur.

The risk of severe babesiosis is higher in certain patients, including:

• Older adults
• People without a functioning spleen
• People with weakened immune systems
• People with certain serious underlying medical conditions

Babesia can also be transmitted through blood transfusion. Because Lyme disease and babesiosis can occur together, severe systemic illness after a tick exposure may require evaluation for more than one tick-borne infection.

How Often Does Lyme Disease Cause Death?

Deaths directly attributed to Lyme disease are rare. Available surveillance and death-certificate data do not support assigning a simple fatality percentage to every diagnosed Lyme disease case.

The best-documented fatal complication is Lyme carditis. The CDC’s 2013 report described three sudden cardiac deaths associated with Lyme carditis. In a subsequent investigation of 121,894 reported Lyme disease cases from selected high-incidence states, only two deaths were classified as suspected Lyme carditis-associated deaths.

These surveillance findings reinforce two points: fatal Lyme disease is extremely uncommon, but cardiac involvement deserves prompt recognition because Lyme carditis can occasionally progress to a life-threatening conduction abnormality.

This is why the more clinically useful question is not simply whether Lyme disease can cause death, but whether a patient has warning signs of a potentially serious complication.

Warning Signs That Require Prompt Evaluation

Cardiac symptoms deserve particular attention in a patient with known or suspected Lyme disease.

Warning signs may include:

• Fainting or near-fainting
• Chest pain
• Shortness of breath
• New or significant palpitations
• Marked lightheadedness
• An unusually slow or irregular heartbeat

Severe neurologic or systemic symptoms also warrant appropriate medical evaluation. Patients should not wait for a routine follow-up visit when potentially serious cardiac symptoms are present.

Early Recognition Matters

Early diagnosis and treatment remain important ways to reduce the risk of serious complications.

Diagnosis may sometimes be delayed when symptoms are attributed to viral illness, anxiety, stress, primary cardiac disease, neurologic disease, or other conditions. This is particularly important with Lyme carditis because cardiac symptoms may occur before Lyme disease has been recognized.

Patients with unexplained cardiac symptoms, syncope, neurologic symptoms, or systemic illness—particularly when there is compatible tick exposure or residence in a Lyme-endemic area—may warrant evaluation for Lyme disease and, when clinically appropriate, other tick-borne infections.

Frequently Asked Questions

What is the fatality rate of Lyme disease?

The fatality rate of Lyme disease is extremely low, but there is no reliable single percentage that applies to all diagnosed cases. A U.S. review of death certificates from 1999 through 2003 found 114 records listing Lyme disease as an underlying or contributing cause of death, but after review only one was consistent with clinical manifestations of Lyme disease. A separate surveillance investigation identified two suspected Lyme carditis-associated deaths among 121,894 reported Lyme disease cases from selected high-incidence states, but that figure should not be interpreted as a universal case-fatality rate.

Can Lyme disease be fatal?

Yes, in rare cases. Lyme carditis is the best-documented potentially fatal complication and can cause dangerous heart conduction abnormalities and, rarely, sudden cardiac death.

Can you die from Lyme disease?

Yes, but deaths directly attributed to Lyme disease are rare. Documented fatal cases have included patients with severe cardiac involvement from Lyme carditis.

Is Lyme disease deadly?

Lyme disease is rarely deadly. Most patients do not develop life-threatening disease, but cardiac involvement can occasionally become dangerous if it is not recognized and treated promptly.

Is Lyme disease fatal if untreated?

Untreated Lyme disease is not inevitably fatal. However, untreated infection can disseminate and cause complications involving the heart, nervous system, or joints. Rare cases of untreated or unrecognized Lyme carditis have resulted in sudden cardiac death.

How survivable is Lyme disease?

Survival is overwhelmingly expected. Death directly attributed to Lyme disease is rare. The major concern is recognizing the uncommon patient who develops a serious complication, particularly Lyme carditis.

Can Babesia kill you?

Yes. Babesiosis is a separate tick-borne infection that can become life-threatening, particularly in older adults, people without a functioning spleen, people with weakened immune systems, and some patients with serious underlying medical conditions.

What are the warning signs of dangerous Lyme disease complications?

Potential warning signs include fainting, chest pain, shortness of breath, significant palpitations, marked lightheadedness, or an unusually slow or irregular heartbeat. Severe neurologic or systemic symptoms also warrant appropriate medical evaluation.

Clinical Takeaway

Lyme disease is rarely fatal, and the available evidence does not support assigning a simple case-fatality percentage to every diagnosed infection.

Death-certificate and surveillance studies reinforce how uncommon Lyme disease-associated mortality is. At the same time, rare deaths have been documented, particularly from Lyme carditis.

Babesiosis can also become life-threatening but should be distinguished from Lyme disease itself because it is a separate tick-borne infection that may occur as a co-infection.

Fainting, chest pain, shortness of breath, significant palpitations, or other signs of possible cardiac involvement in a patient with suspected Lyme disease warrant prompt medical evaluation.

Related Articles

For more on Lyme disease diagnosis, persistent illness, symptoms, and co-infections:

Lyme Disease Misdiagnosis: Why It Happens and What to Know
Persistent Lyme Disease: Why Symptoms Continue After Treatment
Signs and Symptoms of Lyme Disease
Lyme Disease Co-infections: What You Need to Know

References

1. Centers for Disease Control and Prevention. Three Sudden Cardiac Deaths Associated with Lyme Carditis — United States, November 2012–July 2013. MMWR Morb Mortal Wkly Rep. 2013;62(49):993-996.
2. Robinson ML, Kobayashi T, Higgins Y, Calkins H, Melia MT. Lyme carditis. Infect Dis Clin North Am. 2015;29(2):255-268.
3. Yeung C, Baranchuk A. Diagnosis and Treatment of Lyme Carditis: JACC Review Topic of the Week. J Am Coll Cardiol. 2019;73(6):717-726.
4. Kugeler KJ, Griffith KS, Gould LH, Kochanek K, Delorey MJ, Biggerstaff BJ, Mead PS. A review of death certificates listing Lyme disease as a cause of death in the United States. Clin Infect Dis. 2011;52(3):364-367.
5. Forrester JD, Meiman J, Mullins J, et al. Notes from the Field: Update on Lyme Carditis, Groups at High Risk, and Frequency of Associated Sudden Cardiac Death — United States. MMWR Morb Mortal Wkly Rep. 2014;63(43):982-983.
6. Centers for Disease Control and Prevention. Clinical Overview of Babesiosis. CDC. Updated February 13, 2024.

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