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Objectives: Children with epilepsy are at increased risk of complications from vaccine-preventable infections, yet information on vaccine coverage in these children is scarce. We aimed to compare vaccine coverage among children with epilepsy to children without epilepsy., Study Design: We conducted a retrospective cohort study including all 2005-2013 births in Manitoba and Ontario, Canada, creating two cohorts: 2-year-olds and 7-year-olds (followed to age 2 and 7 years). We split each cohort into epilepsy and non-epilepsy subcohorts. We assessed vaccination coverage based on provincial schedules and determined timeliness of MMR (measles, mumps, rubella) dose 1 (recommended at 12 months) and DTaP (diphtheria, tetanus, pertussis) dose 4 (recommended at 18 months). We used logistic regression to calculate adjusted odds ratios (aORs) of the association between epilepsy and vaccination, combining both provincial estimates using random effects meta-analysis., Results: We included 16,558 2-year-olds (Manitoba, 653; Ontario, 15,905) and 13,004 7-year-olds (Manitoba, 483; Ontario, 12,521) with epilepsy. At age 2 years, the aOR for up-to-date vaccination among children with versus without epilepsy was 0.9 (95% confidence interval 0.8-1.1); at age 7 years it was 1.0 (0.9-1.1). Infants diagnosed with epilepsy before age 6 months were less likely to be up-to-date at age 2 years (0.9; 0.8-0.9), although this difference disappeared by age 7 years. Vaccine timeliness was similar between children with and without epilepsy for MMR dose 1 and DTaP dose 4., Conclusions: Overall, this study suggests that children with epilepsy are not significantly under-vaccinated compared to their peers without epilepsy. As children with epilepsy are at a higher risk of complications from vaccine-preventable diseases, vaccination in children with epilepsy should be optimized, especially early in life, as these children may not be able to rely on herd protection., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Crown Copyright © 2021. Published by Elsevier Ltd. All rights reserved.)

Background: In children with epilepsy, fever and illness are known triggers for seizure; therefore, clinicians and parents could be concerned that immunization-induced inflammation and fever could also trigger seizures. We sought to estimate the risk of emergency department (ED) visit or hospitalization for epilepsy/seizure and all causes after immunization in children younger than 7 years of age with epilepsy., Methods: We conducted a self-controlled case series of children diagnosed with epilepsy before their 7th birthday and immunized from 2005 to 2015 in Ontario (population 14.2 million) and Manitoba (population 1.3 million), Canada, using administrative healthcare data. We estimated the age- and season-adjusted relative incidence (aRI) of epilepsy/seizure-related and all-cause ED visits/hospitalizations during various risk periods 0-28 days after inactivated and live immunizations versus a control period 35-83 days postimmunization. Estimates from each province were analyzed separately and then combined in a random-effects meta-analysis., Results: The combined risk of epilepsy/seizure-related hospitalization/ED visit was increased 0-2 days after inactivated vaccines (aRI = 1.5, 95% confidence interval: 1.1-1.9) and 7-10 days after live vaccines (aRI = 1.9, 1.4-2.7). For all-cause ED visit/hospitalization, the combined aRI estimate was 0.9 (0.8-1.2) 0-2 days after inactivated vaccines and 1.3 (1.1-1.5) 7-10 days after live vaccines., Conclusions: The risk of epilepsy/seizure-related ED visit/hospitalization was modestly increased among children with epilepsy during peak periods of fever and inflammation following inactivated and live vaccines. These risks must be balanced against the risk of complications from vaccine-preventable diseases.