Do positive Borrelia and Epstein-Barr virus antibody results show immune recognition rather than active neurologic infection?

Positive Borrelia and Epstein–Barr virus (EBV) antibody findings most reliably document organism-specific humoral immune recognition. They do not, in isolation, identify viable infection, establish timing, or determine the cause of neurologic symptoms.

Clinical interpretation

• For Borrelia, a valid positive result requires a complete, validated two-tier algorithm rather than a reactive screening test or isolated immunoblot band. IgM is particularly unreliable beyond 30 days of illness because persistence and cross-reactivity can yield misleading results.
• Borrelia IgM and IgG can persist for years to decades after eradicated infection; follow-up data document persistence 10–20 years after Lyme disease without evidence of active infection. Thus, serology is not a test of cure or of ongoing infection.
• EBV VCA IgG and EBNA-1 IgG commonly persist lifelong. A VCA-IgG-positive/EBNA-IgG-positive/VCA-IgM-negative pattern generally indicates past infection. Even early-antigen antibodies may persist for years in otherwise healthy people, and IgM-containing patterns can be nonspecific or cross-reactive.

Neurologic attribution and mechanisms

• Serum Borrelia antibodies alone do not establish Lyme neuroborreliosis. Credible attribution requires a compatible syndrome—such as meningitis, painful radiculoneuritis, acute cranial neuropathy, or myelitis—plus appropriate epidemiologic context.
• In suspected CNS Borrelia disease, paired CSF and serum testing is informative: an elevated CSF:serum Borrelia-specific antibody index indicates intrathecal antibody production and is highly specific for CNS involvement. Definite European criteria also include CSF pleocytosis, although intrathecal antibodies may persist after infection.
• EBV serology does not demonstrate CNS infection. Suspected EBV encephalitis requires a compatible encephalitic syndrome, CSF evaluation, and supportive MRI or EEG as appropriate. CSF EBV PCR can support—but cannot independently prove—causation, because low-level positivity may reflect EBV-containing lymphocytes.

Bottom line

• The claim is well supported: positive Borrelia or EBV antibodies show immune recognition, not necessarily current activity or neurologic causation; syndrome-specific clinical, CSF, and ancillary evidence is needed.