Guillain-Barre syndrome; secondary syphilis with early neurosyphilis; This literature-non-study case was reported in a literature article and describes the occurrence of GUILLAIN-BARRE SYNDROME (Guillain-Barre syndrome) and NEUROSYPHILIS (secondary syphilis with early neurosyphilis) in a 51-year-old male patient who received mRNA-1273 (Spikevax) for COVID-19 prophylaxis.   LITERATURE REFERENCE:     The patient's past medical history included COVID-19 in April 2020 and Raynaud's disease. Concurrent medical conditions included Insulin-dependent diabetes mellitus.    On an unknown date, the patient received second dose of mRNA-1273 (Spikevax) (unknown route) 1 dosage form. On an unknown date, the patient experienced GUILLAIN-BARRE SYNDROME (Guillain-Barre syndrome) (seriousness criteria hospitalization and medically significant) and NEUROSYPHILIS (secondary syphilis with early neurosyphilis) (seriousness criteria hospitalization and medically significant). The patient was treated with IMMUNOGLOBULINS NOS (IMMUNOGLOBULIN I.V) (intravenous) for Guillain-Barre syndrome, at an unspecified dose and frequency; DOXYCYCLINE (intravenous) for Empiric treatment, at a dose of 100 milligram twice a day; CEFTRIAXONE (intravenous) for Empiric treatment, at a dose of 2 gram once a day and PENICILLIN G SODIUM for Neurosyphilis, at an unspecified dose and frequency. At the time of the report, GUILLAIN-BARRE SYNDROME (Guillain-Barre syndrome) and NEUROSYPHILIS (secondary syphilis with early neurosyphilis) was resolving.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, CSF test: 1:2 with markedly elevated protein and pleocytosis. On an unknown date, Electromyogram: sensorimotor polyneuropathy with mixed demyelinating and axonal features. On an unknown date, HIV test: (Negative) Negative. On an unknown date, Laboratory test: (Negative) Lyme disease was negative. On an unknown date, Nerve conduction studies: sensorimotor polyneuropathy with mixed demyelinating and axonal features. On an unknown date, Treponema test: returned reactive at 1:64.     For mRNA-1273 (Spikevax) (Unknown), the reporter considered GUILLAIN-BARRE SYNDROME (Guillain-Barre syndrome) and NEUROSYPHILIS (secondary syphilis with early neurosyphilis) to be related.    Concomitant medications were not reported.  Maculopapular rash was appeared on his upper extremities and flanks.  Physical exam was remarkable for bilateral distal motor weakness in the upper and lower extremities with associated paresthesia and decreased reflexes in the lower extremities.  Patient had slight ataxia and difficulty with heel walk and toe walk. Company comment This is a literature non-study case concerning a 51-year-old male patient with no relevant medical history, who experienced the unexpected, serious (medically significant) event of Neurosyphilis and the unexpected, serious (medically significant) adverse event of special interest of Guillain-Barre syndrome. 1 week after receiving the second dose of mRNA-1273 vaccine, the patient started to have bilateral progressive numbness and weakness beginning in his lower extremities and ascending toward his pelvis. He also reported a recent appearance of a maculopapular rash on his upper extremities and flanks. The patient was admitted to a hospital after three weeks. Physical examination was remarkable for bilateral distal motor weakness in the upper and lower extremities with associated paresthesia and decreased reflexes in the lower extremities. The patient had slight ataxia and difficulty with heel walk and toe walk. The cranial nerve exam was normal and the patient was afebrile. Intravenous immune globulin (IVIG) was started empirically for the treatment of Guillain-Barre syndrome (GBS) and doxycycline 100mg intravenous twice a day and ceftriaxone 2g intravenous daily were started for possible tick-borne disease. Subsequently, rapid plasma reagin (RPR) returned reactive at 1:64 and cerebral spinal fluid (CSF) venereal disease research laboratory (VDRL) test was reactive at 1:2 with markedly elevated protein and pleocytosis. Human immunodeficiency virus (HIV) and Lyme disease testing was negative. Nerve conduction studies (NCS) and electromyography (EMG) showed a sensorimotor polyneuropathy with mixed demyelinating and axonal features. IVIG was continued for a total of five days, and antibiotics were changed to penicillin G (PCN G) for a total of 14 days for definitive treatment of early neurosyphilis (NS). Outpatient follow-up one month after treatment completion revealed that the patient's weakness and sensory loss had markedly improved. Additionally, repeat nerve conduction studies did not show any clear evidence of demyelination. The benefit-risk relationship of mRNA-1273 is not affected by this report.; Sender's Comments: This is a literature non-study case concerning a 51-year-old male patient with no relevant medical history, who experienced the unexpected, serious (medically significant) event of Neurosyphilis and the unexpected, serious (medically significant) adverse event of special interest of Guillain-Barre syndrome. 1 week after receiving the second dose of mRNA-1273 vaccine, the patient started to have bilateral progressive numbness and weakness beginning in his lower extremities and ascending toward his pelvis. He also reported a recent appearance of a maculopapular rash on his upper extremities and flanks. The patient was admitted to a hospital after three weeks. Physical examination was remarkable for bilateral distal motor weakness in the upper and lower extremities with associated paresthesia and decreased reflexes in the lower extremities. The patient had slight ataxia and difficulty with heel walk and toe walk. The cranial nerve exam was normal and the patient was afebrile. Intravenous immune globulin (IVIG) was started empirically for the treatment of Guillain-Barre syndrome (GBS) and doxycycline 100mg intravenous twice a day and ceftriaxone 2g intravenous daily were started for possible tick-borne disease. Subsequently, rapid plasma reagin (RPR) returned reactive at 1:64 and cerebral spinal fluid (CSF) venereal disease research laboratory (VDRL) test was reactive at 1:2 with markedly elevated protein and pleocytosis. Human immunodeficiency virus (HIV) and Lyme disease testing was negative. Nerve conduction studies (NCS) and electromyography (EMG) showed a sensorimotor polyneuropathy with mixed demyelinating and axonal features. IVIG was continued for a total of five days, and antibiotics were changed to penicillin G (PCN G) for a total of 14 days for definitive treatment of early neurosyphilis (NS). Outpatient follow-up one month after treatment completion revealed that the patient's weakness and sensory loss had markedly improved. Additionally, repeat nerve conduction studies did not show any clear evidence of demyelination. The benefit-risk relationship of mRNA-1273 is not affected by this report.