This case was reported in a literature article and described the occurrence of myelitis transverse in a subject who received Hib vaccine. On an unknown date, 5 days after receiving Hib vaccine, the subject developed myelitis transverse. Serious criteria included GSK medically significant. The outcome of myelitis transverse was unknown. The investigator considered that there was a reasonable possibility that the myelitis transverse may have been caused by Hib vaccine. Additional information was provided. This case was reported in a literature article and described the occurrence of transverse myelitis (TM) in a patient of unspecified age and gender who was vaccinated with unspecified Hib vaccine (manufacturer unknown). The patient was part of the study that aimed to analyse the association of immunisation and subsequent development of TM or acute disseminated encephalomyelitis (ADEM). All cases of TM and ADEM in the Vaccine Safety Datalink (VSD) population were identified. The study used a case-centered design, which compares vaccination patterns during an exposure interval prior to the outcome in cases vs the entire study population, matched by age, sex, and site. Study population included all children and adults of any age enrolled in the health plants at 6 VSD sites who received 1 or more vaccines during the period from 1 January 2007 through 31 December 2012. No information on patient's medical history or family history or concurrent condition or concomitant medication was provided. On an unspecified date, the patient received unspecified Hib vaccine (administration route and site unspecified; dosages unknown; batch number not provided). On an unspecified date between 1 January 2007 and 31 December 2012, between 5 and 28 day (risk interval) after vaccination, the patient developed TM. (In this study, trained medical records analysts (MRAs) reviewed all identified cases to verify that a neurologist made the diagnosis within 3 months of the first electronic diagnosis, to validate the date of onset, to ensure the diagnosis did not change over time, and to abstract pertinent information. Following this, a neurologist with expertise in demyelinating illnesses reviewed each case. For ADEM, cases were confirmed using the Brighton Collaboration Criteria, and accepted diagnostic levels of certainty 1, 2, and 3 as cases. For TM, the Transverse Myelitis Consortium Working Group criteria were used, because Brighton Criteria were not available. The date of onset used for analysis was that determined by medical record review). Treatment was unknown. The outcome of the event was not reported. The authors commented "for TM, we found no evidence of a safety concern, or any association with subsequent illnesses. If there is any association, it is less than 1 per million doses for vaccines other than live zoster and live attenuated influenza vaccines, and less than 2 per million doses of these 2 vaccines". The authors concluded "TM and ADEM are rarely, if ever, associated with vaccines. If there is an association of ADEM with Tdap, the excess risk is not likely to exceed 1.16 cases of ADEM per million doses of Tdap administered." This is 1 of the 5 valid cases reported in the same literature article.