Lyme Disease and COVID: Effects, Coinfection, and Recovery

Lyme disease and COVID-19 are both significant health concerns, each capable of causing long-term complications. Lyme disease is a bacterial infection transmitted by ticks, while COVID-19 is a viral illness with widespread transmission. When these conditions overlap, they complicate diagnosis, treatment, and recovery.

Understanding their interaction is crucial for recognizing coinfections and managing prolonged symptoms effectively.

Coexistence in Regions Where Ticks Thrive

The geographic overlap of Lyme disease and COVID-19 presents unique challenges for public health, particularly in areas with well-established tick populations. Lyme disease is most prevalent in the northeastern, midwestern, and Pacific coastal regions of the United States, where black-legged ticks thrive in wooded and grassy environments. These same regions have experienced significant COVID-19 outbreaks, creating a dual burden on healthcare systems. The seasonal nature of tick activity further complicates matters, as Lyme disease cases surge in late spring and summer, coinciding with fluctuating COVID-19 transmission.

Climate change has expanded tick habitats, increasing Lyme disease risk in previously unaffected areas. Warmer temperatures and milder winters allow ticks to survive in greater numbers, spreading into higher latitudes. Studies in Environmental Health Perspectives highlight the correlation between rising temperatures and increased tick-borne disease incidence. As a result, regions once considered low-risk for Lyme disease are now facing growing concerns, particularly as healthcare resources remain strained from managing COVID-19.

Human behavior also plays a role. The pandemic led to increased outdoor activities as people sought socially distanced recreation, inadvertently raising exposure to tick habitats. Hiking, camping, and gardening in endemic areas without proper protective measures—such as permethrin-treated clothing or EPA-approved insect repellents—heighten the risk of tick bites. Public health campaigns have attempted to address this by promoting tick awareness alongside COVID-19 precautions, but balancing attention between both threats has been challenging.

Similarities in Early Symptoms

The early symptoms of Lyme disease and COVID-19 overlap, often leading to diagnostic confusion. Both illnesses commonly begin with fatigue, headaches, fever, and muscle aches, making it difficult for clinicians to distinguish between them without laboratory testing. Fever, a hallmark of many infections, is frequently reported in both conditions, though its pattern may differ. Lyme disease tends to cause a low-grade, intermittent fever, whereas COVID-19 often presents with a higher, persistent fever.

Both diseases also cause widespread body aches. Lyme disease triggers deep muscle soreness and joint pain due to inflammation from Borrelia burgdorferi, while COVID-19 induces generalized muscle pain linked to immune system activation. Headaches are another shared symptom. In Lyme disease, headaches may signal early neurological involvement, particularly if accompanied by neck stiffness, which could indicate meningitis. COVID-19 headaches, on the other hand, may result from systemic inflammation, dehydration, or vascular changes, sometimes persisting long after the acute phase.

Fatigue is one of the most debilitating early symptoms of both diseases. Lyme disease can cause profound exhaustion, sometimes mistaken for chronic fatigue syndrome if not properly diagnosed. COVID-19 also induces severe tiredness, with some patients experiencing overwhelming fatigue even in mild cases. This shared characteristic makes differentiation difficult, especially in individuals without respiratory symptoms or the classic Lyme disease rash. While erythema migrans is a defining feature of Lyme disease, it does not appear in all cases, leading to misdiagnosis when symptoms closely resemble those of COVID-19.

Effects on the Immune Response

When Lyme disease and COVID-19 intersect, the immune system must respond to both a bacterial and a viral pathogen simultaneously. Lyme disease provokes an immune response through innate immune cells such as macrophages and dendritic cells, which release pro-inflammatory cytokines like interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α). This inflammation helps control bacterial spread but can also contribute to persistent symptoms if dysregulated. COVID-19, driven by SARS-CoV-2, triggers an overlapping immune response, sometimes leading to a “cytokine storm” in severe cases, with elevated IL-6 and interferon-gamma (IFN-γ) levels exacerbating tissue damage.

The interplay between these immune responses can have unpredictable effects. Some research suggests that prior immune activation from Lyme disease may influence the severity of viral infections, either dampening or amplifying inflammation. Chronic Lyme patients often exhibit immune dysregulation, including altered T-cell function and persistent inflammation, which may affect their ability to fight viral infections. Conversely, a strong immune reaction to COVID-19 might temporarily suppress Borrelia activity, reducing acute Lyme symptoms but potentially increasing long-term complications due to immune exhaustion. This interaction raises concerns about disease progression, particularly for individuals with lingering post-treatment Lyme symptoms or post-acute sequelae of SARS-CoV-2 infection (PASC), commonly known as long COVID.

Identifying Coinfection Cases

Distinguishing between Lyme disease and COVID-19 in coinfected individuals is challenging due to overlapping symptoms. Physicians must rely on clinical history, symptom progression, and targeted testing. A thorough patient history is essential, particularly for those in Lyme-endemic areas or with recent outdoor exposure. Symptoms that persist beyond a typical viral infection, such as prolonged joint pain or neurological issues, may indicate an underlying bacterial coinfection.

Diagnostic testing plays a central role, but timing and test selection are crucial. Standard Lyme disease testing follows a two-tiered approach: an enzyme-linked immunosorbent assay (ELISA) followed by a Western blot if positive. However, early-stage infections may yield false negatives due to delayed antibody production, requiring repeat testing if symptoms persist. COVID-19 is diagnosed through PCR and antigen tests for active infection, while serological tests indicate past exposure. Coinfected patients may initially test positive for COVID-19 but negative for Lyme disease, necessitating follow-up testing if Lyme symptoms remain unresolved.

Duration of Fatigue and Other Lingering Effects

Persistent fatigue is one of the most commonly reported lingering symptoms for individuals recovering from Lyme disease or COVID-19. When both infections occur together, post-illness exhaustion can be particularly prolonged. Lyme disease, even when treated with antibiotics, can lead to post-treatment Lyme disease syndrome (PTLDS), characterized by fatigue, joint pain, and cognitive difficulties lasting months or years. Long COVID presents similar challenges, with symptoms such as brain fog, muscle weakness, and post-exertional malaise persisting long after the acute infection. The overlap of these post-infectious conditions complicates recovery, making it difficult to determine whether lingering symptoms stem from Lyme disease, COVID-19, or both.

Neurological symptoms add to the complexity. Lyme neuroborreliosis can cause memory impairment, difficulty concentrating, and nerve pain, mirroring cognitive symptoms seen in long COVID. Patients with both conditions may experience extended cognitive dysfunction due to their combined impact on the nervous system. Sleep disturbances, including insomnia, unrefreshing sleep, or hypersomnia, are also common post-infectious complications. Addressing these lingering effects requires a tailored approach, incorporating graded exercise therapy, cognitive rehabilitation, and symptom-targeted treatments. A multidisciplinary approach to care is essential, ensuring that patients with dual infections receive comprehensive support for managing prolonged symptoms.