This case was reported in a literature article and described the occurrence of acute disseminated encephalomyelitis in a subject who received dTpa vaccine. Co-suspect products included human papillomavirus quadrivalent vaccine. On an unknown date, 43 days after receiving dTpa vaccine, Hepatitis A vaccine and Meningococcal ACWY vaccine, the subject developed acute disseminated encephalomyelitis. Serious criteria included GSK medically significant. The outcome of acute disseminated encephalomyelitis was unknown. The investigator considered that there was a reasonable possibility that the acute disseminated encephalomyelitis may have been caused by dTpa vaccine, Hepatitis A vaccine and Meningococcal ACWY vaccine. Additional information was provided. This case was reported in a literature article and described the occurrence of acute disseminated encephalomyelitis (ADEM) in a patient of unspecified age and gender who was vaccinated with unspecified Tdap, unspecified hepatitis A, unspecified MCV4 and unspecified HPV4 vaccines (manufacturer unknown for all). This case corresponds to discussion section in this literature article. The patient was part of the study that aimed to analyse the association of immunisation and subsequent development of transverse myelitis (TM) or 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 plans at 6 VSD sites who received 1 or more vaccines during the period from 01 January 2007 through 31 December 2012. The patient belonged to comparison period. 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 Tdap, unspecified hepatitis A, unspecified MCV4 and unspecified HPV4 vaccines (administration route and site unspecified; dosages unknown; batch number not provided for all) at the same time. The patient was immunised routinely. On an unspecified date between 1 January 2007 and 31 December 2012, between 43 days through 9 months (comparison interval) after vaccination, the patient developed ADEM. (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). Treatment was unknown. The outcome of the event was not reported. The authors commented "for ADEM, we found a possible association with the Tdap vaccine in the 5 to 28 day risk interval." The authors did not comment on the relationship between the event of ADEM and unspecified hepatitis A, unspecified MCV4 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.