ARTICLE Epilepsy in Children After Pandemic Influenza Vaccination Siri E. Håberg, MD, PhD, a Kari M. Aaberg, MD, a,b Pål Surén, MD, PhD, a,b Lill Trogstad, MD, PhD, a Sara Ghaderi, MSc, PhD, a Camilla Stoltenberg, MD, PhD, a,c Per Magnus, MD, PhD, a,d Inger Johanne Bakken, MSc, PhD a OBJECTIVES: To determine if pandemic influenza vaccination was associated with an increased risk of epilepsy in children. METHODS: Information from Norwegian registries from 2006 through 2014 on all children <18 years living in Norway on October 1, 2009 was used in Cox regression models to estimate hazard ratios for incident epilepsy after vaccination. A self-controlled case series analysis was used to estimate incidence rate ratios in defined risk periods after pandemic vaccination. RESULTS: In Norway, the main period of the influenza A subtype H1N1 pandemic was from October 2009 to December 2009. On October 1, 2009, 1 154 113 children <18 years of age were registered as residents in Norway. Of these, 572 875 (50.7%) were vaccinated against pandemic influenza. From October 2009 through 2014 there were 3628 new cases of epilepsy (incidence rate 6.09 per 10 000 person-years). The risk of epilepsy was not increased after vaccination: hazard ratio: 1.07; 95% confidence interval: 0.94 –1.23. Results from the self-controlled case series analysis supported the finding of no association between vaccination and subsequent epilepsy. CONCLUSIONS: Pandemic influenza vaccination was not associated with increased risk of epilepsy. Concerns about pandemic vaccination causing epilepsy in children seem to be unwarranted. abstract a Norwegian Institute of Public Health, Oslo, Norway; b The National Center for Epilepsy, Oslo University Hospital, Oslo, Norway; c Department of Global Public Health and Community Care, University of Bergen, Bergen, Norway; and d Institute of Health and Society, University of Oslo, Oslo, Norway Dr Håberg conceptualized and designed the study, was responsible for the data collection and the analytics plan, and drafted the initial manuscript; Dr Bakken contributed to the data collection and the analytics plan, conducted the analyses, and reviewed and revised the manuscript; Drs Trogstad, Magnus, and Stoltenberg contributed to the conceptualization and design of the study, and the interpretation of results, and critically reviewed the manuscript; Drs Ghaderi, Surén, and Aaberg contributed to the interpretation of results, and critically reviewed the manuscript; and all authors approved the final manuscript as submitted. DOI: https://doi.org/10.1542/peds.2017-0752 Accepted for publication Dec 5, 2017 Address correspondence to Siri E. Håberg, MD, PhD, Norwegian Institute of Public Health, PO Box 4404 Nydalen, 0403 Oslo, Norway. E-mail: siri.haberg@fhi.no PEDIATRICS (ISSN Numbers: Print, 0031-4005; Online, 1098-4275). Copyright © 2018 by the American Academy of Pediatrics FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose. POTENTIAL CONFLICTS OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose. PEDIATRICS Volume 141, number 3, March 2018:e20170752 WHAT’S KNOWN ON THIS SUBJECT: Influenza vaccination has been associated with an increased risk of febrile seizures in children. There is a link between febrile seizures, particularly complex febrile seizures, and an increased risk of later epilepsy. WHAT THIS STUDY ADDS: Concerns about pandemic vaccination increasing the risk of epilepsy in children seem to be unwarranted. To cite: Håberg SE, Aaberg KM, Surén P, et al. Epilepsy in Children After Pandemic Influenza Vaccination. Pediatrics. 2018;141(3):e20170752 by guest on June 1, 2020 www.aappublications.org/news Downloaded from