Lyme Reinfection: Why You Can Get Lyme Disease More Than Once

Lyme reinfection is well documented, and research suggests patients may develop strain-specific immunity rather than full protection against future infections.

Many patients assume prior Lyme disease protects them—but this is often not the case.

“It is common knowledge among veterinarians who practice in Lyme disease endemic areas that a significant percentage of dogs will develop repeated infections,” writes Khatchikian.

This phenomenon has also been observed in humans. “In one study, 15% of patients with Lyme disease living in an endemic area developed one or more follow-up infections within five years,” he explains.

Prior infection does not appear to provide complete immunity.

Why Reinfection Occurs

“Many patients treated for early Lyme disease incur another infection in subsequent years, suggesting that previous exposure to Borrelia burgdorferi may not elicit a fully protective immune response,” Khatchikian writes.

However, identical strains are almost never detected in patients with multiple infections.

This finding suggests that infection may confer protection only against the same strain—while leaving patients vulnerable to different strains.

Clinical Implications

Strain-specific immunity helps explain why patients can develop Lyme disease more than once, particularly in endemic regions.

It also raises important considerations for prevention, diagnosis, and vaccine development.

Learn more about Lyme disease testing and diagnosis and why repeat infections can complicate clinical evaluation.

Clinical Perspective

Patients with a prior history of Lyme disease should not assume they are protected from future infection.

Ongoing exposure to ticks in endemic areas can lead to reinfection with a different strain of Borrelia burgdorferi, resulting in new or recurrent symptoms.

Diversity of Borrelia burgdorferi strains may explain treatment failures

Re-infection with different B. burgdorferi strain can cause a super-infection in mice

References:

Izac JR, Marconi RT. Diversity of the Lyme Disease Spirochetes and its Influence on Immune Responses to Infection and Vaccination. Vet Clin North Am Small Anim Pract. 2019.
Khatchikian CE, Nadelman RB, Nowakowski J, Schwartz I, Wormser GP, Brisson D. Evidence for strain-specific immunity in patients treated for early Lyme disease. Infect Immun. 2014;82(4):1408-1413.
Nowakowski J, Nadelman RB, Sell R, et al. Long-term follow-up of patients with culture-confirmed Lyme disease. Am J Med. 2003;115(2):91-96.

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