Skip to main content Accessibility help
×
×
Home

Pandemic H1N1 Vaccination and Incidence of Acute Disseminated Encephalomyelitis in Manitoba

  • Alan C. Jackson (a1) (a2), Luiz C. Mostaço-Guidolin (a3) (a4), Hasantha Sinnock (a3), Songul Bozat-Emre (a3) (a4), Michael Routledge (a3) (a4) and Salaheddin M. Mahmud (a3) (a5) (a4)...
Abstract

Background: An increased incidence of hospital admissions coded as acute disseminated encephalomyelitis (ADEM) was noted in Winnipeg, Manitoba, Canada, during the second wave of the influenza pandemic from October 2009 to March 2010. However, it was not clear whether this was due to heightened awareness of potential neurological complications of influenza or influenza vaccination or an actual increase in the number of cases. Methods: We extracted data from the charts of 139 patients hospitalized with an International Classification of Diseases-10 discharge code indicating ADEM (G04.0) or unspecified noninfectious encephalitis or myelitis (G04.8, G04.9) between January 2006 and December 2012. Clinical and laboratory data were reviewed by a neurologist, and diagnoses were determined using the Brighton criteria. Results: Over the entire study period, there were 22 cases of ADEM. During the peak pandemic period (April-December 2009), seven patients were hospitalized with ADEM, corresponding to a rate of 7.8/million/year; 4.7 (95% confidence interval: 1.9-11.4) times higher than the rate before or after the pandemic period. Only one patient with ADEM had received the monovalent A(H1N1)pdm09 vaccine within 12 weeks of hospitalization. Conclusions: We have found an increased incidence of ADEM during the pandemic period that may be related, at least in part, to the increased incidence of influenza during that period. However, there was no temporal relationship with the administration of A(H1N1)pdm09 or seasonal influenza vaccines. Our study provides reassurance that use of these vaccines was not associated with increased risk of ADEM.

Vaccination H1N1 en période de pandémie et incidence d’encéphalomyélite disséminée aiguë au Manitoba. Contexte: Une augmentation de l’incidence des hospitalisations dont le code consigné au dossier indiquait que le patient souffrait d’une encéphalomyélite disséminée aiguë (EMDA) a été notée à Winnipeg, Manitoba, Canada, pendant la deuxième vague de la pandémie d’influenza, soit d’octobre 2009 à mars 2010. Cependant, il n’était pas clair si ceci était dû à une prise de conscience des complications neurologiques potentielles de l’influenza ou à la vaccination contre l’influenza ou d’une véritable augmentation du nombre de cas. Méthodologie: Nous avons extrait les données des dossiers de 139 patients hospitalisés entre janvier 2006 et décembre 2012 dont le code indiquait que le patient souffrait d’une EMDA (G04.0) ou d’une encéphalite ou d’une myélite non infectieuse non spécifiées (G04.8, G04.9) selon la Classification internationale des maladies-10 au moment du congé hospitalier. Les données cliniques et de laboratoire ont été revues par un neurologue et les diagnostics ont été établis selon les critères de Brighton. Résultats: Au cours de la période de l’étude, il y a eu 22 cas d’EMDA. Au moment du point culminant de la pandémie (avril à décembre 2009), sept patients atteints d’une EMDA ont été hospitalisés, ce qui correspond à un taux de 7,8/million/année, soit 4,7 fois plus élevé (intervalle de confiance à 95% : 1,9 à 11,4) que le taux avant ou après la période de pandémie. Seulement un patient atteint d’EMDA avait reçu le vaccin monovalent A(H1N1)pdm09 au cours des douze semaines précédant l’hospitalisation. Conclusions: Nous avons constaté une incidence accrue d’EMDA pendant la pandémie ce qui pourrait être en relation, du moins en partie, à une incidence accrue d’influenza pendant cette période. Cependant, il n’existait pas de relation temporelle avec l’administration de A(H1N1)pdm09 ou de vaccins saisonniers contre l’influenza. Notre étude montre que l’utilisation de ces vaccins n’était pas associée à un risque accru d’EDMA, ce qui est rassurant.

  • View HTML
    • Send article to Kindle

      To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      Pandemic H1N1 Vaccination and Incidence of Acute Disseminated Encephalomyelitis in Manitoba
      Available formats
      ×
      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      Pandemic H1N1 Vaccination and Incidence of Acute Disseminated Encephalomyelitis in Manitoba
      Available formats
      ×
      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      Pandemic H1N1 Vaccination and Incidence of Acute Disseminated Encephalomyelitis in Manitoba
      Available formats
      ×
Copyright
Corresponding author
Correspondence to: Alan C. Jackson, Health Sciences Centre, GF-543, 820 Sherbrook Street, Winnipeg, MB R3A 1R9 Canada. Email: ajackson2@hsc.mb.ca.
References
Hide All
1. Patterson, KD, Pyle, GF. The geography and mortality of the 1918 influenza pandemic. Bull Hist Med. 1991;65:4-21.
2. Davis, LE, Koster, F, Cawthon, A. Neurologic aspects of influenza viruses. In: Tselis AC, Booss J, editors. Handbook of clinical neurology: neurovirology. Amsterdam: Elsevier; 2014, p. 619-645.
3. Trifonov, V, Khiabanian, H, Rabadan, R. Geographic dependence, surveillance, and origins of the 2009 influenza A (H1N1) virus. N Engl J Med. 2009;361:115-119.
4. Shoamanesh, A, Traboulsee, A. Acute disseminated encephalomyelitis following influenza vaccination. Vaccine. 2011;29:8182-8185.
5. Sejvar, JJ, Kohl, KS, Bilynsky, R, et al. Encephalitis, myelitis, and acute disseminated encephalomyelitis (ADEM): case definitions and guidelines for collection, analysis, and presentation of immunization safety data. Vaccine. 2007;25:5771-5792.
6. Ussel, IV, Boer, W, Parizel, P, Cras, P, Jorens, PG. Encephalitis related to a H1N1 vaccination: case report and review of the literature. Clin Neurol Neurosurg. 2014;124:8-15.
7. Cardenas, G, Soto-Hernandez, JL, Diaz-Alba, A, et al. Neurological events related to influenza A (H1N1) pdm09. Influenza Other Respir Viruses. 2014;8:339-346.
8. Roberts, JD, Poffenroth, LA, Roos, LL, Bebchuk, JD, Carter, AO. Monitoring childhood immunizations: a Canadian approach. Am J Public Health. 1994;84:1666-1668.
9. Mahmud, S, Hammond, G, Elliott, L, et al. Effectiveness of the pandemic H1N1 influenza vaccines against laboratory-confirmed H1N1 infections: population-based case-control study. Vaccine. 2011;29:7975-7981.
10. Liang, XF, Li, L, Liu, DW, et al. Safety of influenza A (H1N1) vaccine in postmarketing surveillance in China. N Engl J Med. 2011;364:638-647.
11. Manzoli, L, De, VC, Salanti, G, D’Addario, M, Villari, P, Ioannidis, JP. Meta-analysis of the immunogenicity and tolerability of pandemic influenza A 2009 (H1N1) vaccines. PLoS ONE. 2011;6:e24384.
12. Vellozzi, C, Broder, KR, Haber, P, et al. Adverse events following influenza A (H1N1) 2009 monovalent vaccines reported to the Vaccine Adverse Event Reporting System, United States, October 1, 2009-January 31, 2010. Vaccine. 2010;28:7248-7255.
13. Nakayama, T, Onoda, K. Vaccine adverse events reported in post-marketing study of the Kitasato Institute from 1994 to 2004. Vaccine. 2007;25:570-576.
14. Koelman, DL, Mateen, FJ. Acute disseminated encephalomyelitis: current controversies in diagnosis and outcome. J Neurol. 2015;262:2013-2022.
15. Leake, JA, Albani, S, Kao, AS, et al. Acute disseminated encephalomyelitis in childhood: epidemiologic, clinical and laboratory features. Pediatr Infect Dis J. 2004;23:756-764.
16. Wang, J, Duan, S, Zhao, J, Zhang, L. Acute disseminated encephalomyelitis associated with influenza A H1N1 infection. Neurol Sci. 2011;32:907-909.
17. Ozkale, Y, Erol, I, Ozkale, M, Demir, S, Alehan, F. Acute disseminated encephalomyelitis associated with influenza A H1N1 infection. Pediatr Neurol. 2012;47:62-64.
18. Garazzino, S, Gabiano, C, Calitri, C, et al. A case of acute disseminated encephalomyelitis following influenza virus A-H1N1 infection. Minerva Pediatr. 2013;65:565-567.
19. Mahmud, SM, Becker, M, Keynan, Y, et al. Estimated cumulative incidence of pandemic (H1N1) influenza among pregnant women during the first wave of the 2009 pandemic. CMAJ. 2010;182:1522-1524.
20. Thompson, LH, Mahmud, SM, Keynan, Y, et al. Serological survey of the novel influenza A H1N1 in inner city Winnipeg, Manitoba, 2009. Can J Infect Dis Med Microbiol. 2012;23:65-70.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Canadian Journal of Neurological Sciences
  • ISSN: 0317-1671
  • EISSN: 2057-0155
  • URL: /core/journals/canadian-journal-of-neurological-sciences
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Keywords

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed