bb‐Chen 2018.
| Study characteristics | ||
| Methods | Nested case–control study between January 2011 and December 2015 ‐ China | |
| Participants | Case: from the hospital information system's first mention of International Classification of Diseases, 10th Revision (ICD‐10) diagnostic codes (G04.001, G04.002, G04.051, G04.903, G04.912) for ADEM from 1 January 2011 to 31 December 2015, for individuals of any age. Diagnoses were confirmed by neurologists from clinical data, such as clinical manifestations, CT, EEG, CSF, and MRI examinations. N = 272 Controls: for each ADEM case, 4 control individuals randomly selected from the same hospital with no history of ADEM were matched to the case according to year of birth (within 1 year), gender, and zip code (a surrogate measure for socioeconomic status) during the same period. The control participants were assigned the same index date as their matched case (symptom onset date). Controls were patients referred for headache (except trigeminal neuralgia), migraine, vascular, or other diseases that were thought not to modify the probability of vaccination. Patients with chronic severe neurological diseases or autoimmune diseases were excluded. N = 1096 |
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| Interventions | MMR vaccination | |
| Outcomes | Information on vaccinations was obtained from the Information Management System for Immunization Programming, in which anyone who received vaccinations would have been registered, matched with ID number and verified by paper vaccination records. Any vaccination was considered to be an exposure. The trial authors collected information on all vaccinations received within 180 days. | |
| Funding Source | Government | |
| Notes | Conclusions: findings from the present study do not demonstrate an association of vaccines with an increased risk of ADEM and its recurrence among either paediatric (< 18 years) or adult (≥ 18 years) individuals within the 180 days after vaccinations. | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| CCS ‐ case selection | Low risk | Adequate ‐ secure record ‐ diagnoses were confirmed by neurologists |
| CCS ‐ control selection | Low risk | Adequate ‐ hospital control |
| CCS ‐ comparability | Low risk | Adequate ‐ matching for age, gender, address |
| CCS ‐ exposures | Low risk | Adequate ‐ secure record |
| Summary Risk of Bias assessment | Low risk | Plausible bias is unlikely to have seriously altered the results. |