This case was reported in a literature article and described the occurrence of neuromyelitis optica in a 28-year-old male patient who received Hepatitis B vaccine. Co-suspect products included DTPa vaccine. On an unknown date, the patient received Hepatitis B vaccine (unknown) and DTPa vaccine (unknown). On an unknown date, 11 days after receiving Hepatitis B vaccine and 13 days after receiving DTPa vaccine, the patient experienced neuromyelitis optica (serious criteria hospitalization and GSK medically significant), pain in eyes, low vision, both eyes, loss of vision (serious criteria GSK medically significant), numbness, tingling sensation, fatigue, incoordination, balance difficulty, relative afferent pupillary defect and optic disc pallor excessive (serious criteria GSK medically significant). The patient was treated with Steroids, plasma and mycophenolate mofetil. On an unknown date, the outcome of the neuromyelitis optica, pain in eyes, low vision, both eyes, numbness, tingling sensation, incoordination, balance difficulty, relative pupillary defect and optic disc pallor excessive were recovering/resolving and the outcome of the loss of vision was recovered/resolved and the outcome of the fatigue was unknown. The reporter considered the neuromyelitis optica, pain in eyes, low vision, both eyes, loss of vision, numbness, tingling sensation, fatigue, incoordination, balance difficulty, relative afferent pupillary defect and optic disc pallor excessive to be probably related to Hepatitis B vaccine. The reporter considered the neuromyelitis optica, pain in both eyes, low vision, both eyes, loss of vision, numbness, tingling sensation, fatigue, incoordination, balance difficulty, relative afferent pupillary defect and optic disc pallor excessive to be possibly related to DTPa vaccine. Additional information received: This case was reported in a literature article and it described the occurrence of seronegative neuromyelitis optica spectrum disorder in a 28-year-old male patient who had received an unspecified hepatitis B vaccine and an unspecified Tdap vaccine (manufacturers unknown). The patient was a graduate student about to commence the academic semester who did not have any relevant medical history according to the authors. No further information on the patient's concurrent medical conditions, medical or family history, or concomitant medication was provided. On an unspecified date, the patient received a dose of an unspecified hepatitis B vaccine and an unspecified Tdap vaccine (dosage unknown; administration route and site unspecified; batch number not provided). On an unspecified date, 11 days after the vaccination, the patient developed pain when moving the eyes bilaterally. Within 24 hours of the onset of the pain, he started to experience decreased vision in both eyes that progressed to complete vision loss within 1 day; as well as numbness and tingling sensations ascending from his feet to his mid-thoracic region that were associated with fatigue, incoordination and loss of balance. However his strength was not affected according to the authors. The patient required admission to the hospital where he was initially diagnosed with optical neuritis based on the presence of bilateral relative afferent pupillary defects, bilateral optic disc pallor, and enhancement of the optic nerves on magnetic resonance imaging. The patient was later seen by the authors on a follow-up visit; they believed that this was a case of seronegative neuromyelitis optica spectrum disorder in view of the bilateral optic neuritis, the longitudinally extensive thoracic spine lesion that spanned for three segments and that the results of the brain magnetic resonance imaging did not indicate multiple sclerosis. This was a serious case as the patient required admission. Magnetic resonance imaging of the thoracic spine showed a large non-enhancing lesion involving the right side of the spinal cord that extended from T6 to T9, as well as a second smaller lesion involving the posterior central thoracic spinal cord at T5 level. Brain magnetic resonance imaging revealed contrast enhancement of bilateral optic nerves on T1-weighted imaging consistent with optic neuritis, as well as a non-enhancing T2 lesion with restricted diffusion at the junction of the right thalamus and posterior limb of the internal capsule. Cerebrospinal fluid analysis revealed a cell count differential of 1/ul (within normal limits according to the authors, range not provided), absence of oligoclonal bands, as well as normal glucose, protein and immunoglobulin G index. Enzyme-linked immunosorbent assay of the aquaporin-4 immunoglobulin G autoantibodies in serum was negative. A complete magnetic resonance imaging was performed on a follow-up visit after 9 months. The neurological findings identified previously seemed to be stable and no new lesions were noted. Initial treatment consisted of intravenous steroids (unspecified) and 5 sessions of plasma exchange during his hospitalisation. This was followed by weekly plasma exchange for 4 weeks after discharge and prescription of mycophenolate mofetil (dosage unknown) that was well tolerated and still ongoing 9 months later. The outcome of the visual disturbances was recovering 9 months after the onset. According to the authors, the recovery had commenced during the hospitalisation and had also been documented on a follow-up visit 3 weeks after discharge where he had reported a restoration of colour, shapes and details, but with the left eye vision remaining subjectively 'darker' than the right. The outcome of the numbness and tingling sensations was recovering 9 months after the onset too, having significantly decreased by the 3-week follow up and being almost resolved 9 months after the event. The coordination and balance difficulties had also improved 3 months after he was discharged and their outcome was almost resolved 9 months after the onset. The neurological findings were stable on a magnetic resonance imaging performed 9 months after presentation and no new lesions were noted. The authors believed that the events were more likely to be related to the hepatitis B vaccine than to the Tdap vaccine. However they recognised that establishing a causal relationship between vaccination and this type of events through the temporal association of rare events was difficult. The authors concluded that "while previous case reports have described temporal associations between several central-nervous-system demyelinising diseases and preceding exposure to recombinant hepatitis B vaccine, to the best of our knowledge this case represents the first published report of seronegative neuromyelitis optica spectrum disorder onset following administration of hepatitis B vaccine. A recent review of the literature from 1979 to 2013 found 7 cases of neuromyelitis optica spectrum disorder onset or relapse (both seropositive and seronegative for AQP4-IgG) associated with exposure to various vaccines, with the vaccine against human papilloma virus being the most commonly implicated. One potential limitation of this case is that our patient also received the Tdap vaccine prior to the seronegative neuromyelitis optica spectrum disorder onset; however, we think this is unlikely to be of pathogenic significance given that we were unable to find any published reports linking Tdap vaccine exposure to central-nervous-system demyelinising disease. Although it is difficult, if not impossible, to establish a causal relationship between vaccination and central-nervous-system demyelinising disease through the temporal association of rare events described in case reports such as this, we nevertheless believe it is important to make such cases known, both to contribute to the continued development of safe and efficacious methods of vaccination, as well as to provoke further investigation into the pathogenesis of seronegative neuromyelitis optica spectrum disorder, which may lead to a more refined nosology of this evolving spectrum of disease".