Lyme Disease Reinfection: Why It Happens

Can you get Lyme disease more than once?
Yes—and it’s more common than many expect.
Prior infection may not protect you.

Lyme disease reinfection is well recognized in both animals and humans living in endemic areas.

Veterinarians have long observed that dogs frequently develop repeated Lyme disease infections. According to Khatchikian, this pattern is also seen in humans.

In one study, approximately 15% of patients with Lyme disease developed one or more subsequent infections within five years.

Key insight: prior infection does not reliably prevent future Lyme disease.

Why Reinfection Occurs

Many patients treated for early Lyme disease go on to develop new infections in later years.

This suggests that exposure to Borrelia burgdorferi does not always produce a fully protective immune response.

Clinical issue: immunity after infection may be incomplete.

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Strain-Specific Immunity

Interestingly, studies have shown that patients who are infected multiple times rarely acquire the same strain of B. burgdorferi.

This suggests that infection may provide strain-specific immunity—but not protection against other strains.

Clinical pattern: reinfection often involves a different strain rather than relapse of the original infection.

What This Means for Patients

Patients who have had Lyme disease remain at risk for future infections—especially if they continue to live in or visit endemic areas.

Prevention remains essential, even after successful treatment.

Perform regular tick checks
Use protective clothing and repellents
Monitor for early symptoms after outdoor exposure

Clinical Takeaway

Lyme disease reinfection is not uncommon and may reflect exposure to different strains of the bacteria.

Prior infection does not guarantee protection, making prevention and early recognition critical.

Key question: Could recurrent symptoms reflect a new infection rather than persistence of the original one?

Diversity of Borrelia strains and treatment outcomes
Reinfection with different strains in Lyme disease

References:

Izac JR, Marconi RT. Diversity of Lyme disease spirochetes. Vet Clin North Am Small Anim Pract. 2019.
Khatchikian CE, et al. Evidence for strain-specific immunity in Lyme disease. Infect Immun. 2014.
Nowakowski J, et al. Long-term follow-up of Lyme disease patients. Am J Med. 2003.

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